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Low ionic concentrations and the chemical stability of the ions involved to water are considered necessary for hydrated ionic solution lubricants. Herein, an ultra-high concentration of chemically active ZnCl2 aqueous solution (up to 20 mol L− 1) is first reported to be used as a liquid superlubricant, with trace amounts of Zn2+ hydrolyzed to generate Zn(OH)2 (i.e., hard clusters) in addition to Zn2+ hydrated with water (i.e., soft clusters), resulting in the formation of heterogeneous phases with a mixture of soft and hard clusters. The coefficient of friction (COF) inversely correlates with the molar concentration of ZnCl2, where the COF of the optimized samples can be as low as 0.006 with a stable macroscopic superlubricated state; the particle size distribution of clusters and their corresponding Spans, however, are positively correlated with the molar concentration, suggesting that asymmetric contact between these unequal-sized soft and hard clusters contributes greatly to the reduction of interfacial shear resistances. This ultra-high-concentration aqueous solution superlubricant not only breaks the convention but also deepens the mechanism of liquid superlubricity from the perspectives of cluster size distribution and interactions between clusters, providing a new insight into the design of advanced water-based ionic solution superlubricants. [ABSTRACT FROM AUTHOR]

Adding additives (e.g., carbon dots, CDs) to liquid lubricants is an effective method for enhancing their load‐bearing capacity and friction reduction. However, it is challenging to simultaneously impart high load‐bearing capacity and superlubricity for them (e.g., ionic liquid analogs, ILAs) through this strategy due to strong Coulombic interactions. With CDs as a competing ligand operon, the cluster size distribution can be expanded, conferring superlubricity with ultrahigh load‐bearing capacity (>705 MPa, the highest value of CDs‐based superlubricious materials thus far) for CDs/ILAs. In particular, methodologies such as Raman, 1H‐NMR, fourier transform infrared spectroscopy, and laser particle size analysis are employed to characterize the evolution of their H‐bonding interactions and particle size distribution. CDs can act as competing ligands and enable CDs/ILAs to form systems with ultra‐low coefficient of friction and wear consisting of a mixture of large and small clusters. The mixed and expanded size clusters facilitate the reduction of the viscosity for CDs/ILAs under shear, thereby reducing the interfacial shear resistance during superlubricity, while the CDs within them efficiently transfer the normal bearing loads. The progress is made from the perspective of cluster particle size distribution rather than individual additive properties, providing a new avenue for designing ILAs‐based superlubricious materials. [ABSTRACT FROM AUTHOR]

Soil salinization is a serious problem leading to ecological degradation. Melia azedarach is highly salt‐tolerant, and its application to saline‐alkali land is a promising strategy for restoring degraded lands. However, most studies only focus on the salt‐reducing effect of herbs on saline‐alkali land, and there are few studies on the metabolic adaptation mechanism of trees in the process of soil restoration in coastal saline‐alkali land. In this study, we analyzed the soil properties and metabolome of M. azedarach roots grown in low‐ (<3 g/kg; L), medium‐ (5 ~ 8 g/kg; M), and high‐ (>10 g/kg; H) salinity soils to explore the amelioration effect and adaptation mechanism of M. azedarach to soils with differential salinity. Cultivation of M. azedarach was associated with a decrease in the concentration of Na+ and increases in organic matter content and alkaline phosphatase and urease activities in the rhizosphere soil. The metabolome analysis revealed that a total of 382 (ESI+) and 277 (ESI−) differential metabolites (DEMs) were detected. The number of DEMs in roots rose with increased soil salinity, such as sugars and flavonoids in H versus L, and amino acids in M versus L. The most up‐regulated DEMs were 13‐S‐hydroxyoctadecadienoic acid, 2′‐Deoxyuridine, and 20‐hydroxyleukotriene B4. Combined analysis of soil properties and M. azedarach DEMs indicated that alkaline phosphatase activity was positively correlated with traumatic acid concentration. Taken together, these results indicate that M. azedarach has the potential to reduce soil salinity and enhance soil enzyme activity, and it can adapt to salt stress by regulating metabolites like sugars, amino acids, and flavonoids. This study provides a basis for understanding the mechanism underlying the adaptation of M. azedarach to saline‐alkali soil and its amelioration. [ABSTRACT FROM AUTHOR]

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Intense human activities break the grassland–livestock balance and accelerate grassland degradation. We evaluated the use of native dominant species combined with arbuscular mycorrhizal fungi (AMF) in order to recover grassland and restrain grassland degradation. We conducted a full factorial greenhouse experiment to evaluate the interaction effects of native species of distinct traits grass Lolium perenne (L) and legume Trifolium repens (T) with arbuscular mycorrhizal fungi (AMF) inoculation on grass productivity and soil properties across non-degraded, lightly degraded, and severely degraded soils. The grass–legume mixture was manipulated with five ratios (T:L = 1:0, T:L = 1:1, T:L = 3:1, T:L = 1:3, T:L = 0:1). The results showed that L. perenne significantly increased grassland productivity at different grass–legume ratios, regardless of AMF presence or absence. AMF inoculation increased plant N and P content uptake and improved the productivity of degraded grasslands, especially in severely degraded grasslands. The NO3−-N and available P concentrations increased in soil when the legume component increased from T:L = 0:1 (grass monoculture) to T:L = 1:0 (legume monoculture). This may be because the presence of Lolium perenne (L) can promote nitrogen fixation in legumes. Structural equation modeling indicated that grass–legume mixtures directly affected plant biomass, whereas AMF affected plant biomass via providing plant nutrients. A soil quality index based on minimum datasets indicated a significant positive effect of artificial grassland establishment on soil quality. We conclude that planting T:L = 0:1 and T:L = 1:3 combined with AMF inoculation can be used to recover degraded grassland production, and planting T:L = 1:1 and T:L = 1:3 plus AMF inoculation can be applied for grassland nutrient accumulation and stability maintenance. [ABSTRACT FROM AUTHOR]