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The ethylene-methyl acrylate copolymer (EMA)/nitrile rubber (NBR) thermoplastic vulcanizates (TPV) (EMA/NBR TPV) were prepared by dynamic vulcanization, the dynamic mechanical properties and thermal stability of EMA/NBRTPV were studied, the influence of mass ratio of EMA to NBR, deformation temperature and recovery tempe-rature on the shape memory properties of EMA/NBR TPV under compression mode were investigated syetematically.The microstructure of EMA/NBR TPV was observed and the mechanism of shape memory behavior was proposed.Experimental results showed that EMA/NBR TPV had a typical "sea-island" microstructure, and there was an obvious orientation microstructure on the fracture surface under compression mode; the result of dynamic mechanical analysis showed that EMA and NBR had well compatibility; the result of differential scanning calorimetry testing showed the melting temperature of EMA/NBR TPV was about 98 ℃; the shape fixity ratio of EMA/NBR TPV was increased and the shape recovery ratio was decreased with the increasingmass ratio of plastic phase, while the shape recovery ratio was increased and the shape fixity ratio of EMA/NBR TPV was decreased with the increasing mass ratio of rubber phase.When the deformation temperature was 95 ℃ and the recovery temperature was 100 ℃, EMA/NBR TPV had the best shape memory performance.

Exploring and quantifying the impacts of biological soil crusts on soil hydrological processes and soil water budget in semi-arid ecosystems can provide a theoretical basis for vegetation restoration and reconstruction in deserts. Based on continuous observation of soil water content in different types of areas covered by biological soil crusts ( e.g. , algae, moss) and bare sand in the Mu Us sandy land during the growing season (May to October) from 2018 to 2020, we examined the effects of biological soil crusts on soil water budget at a depth of 0-40 cm. Results showed that algae and moss crusts significantly reduced soil water supplement below 40 cm by rainfall and increased soil water evaporation loss, compared with that under bare sand. In the relatively wet year (2018), the amount of soil water expenditure (seepage+evaporation) covered by bare sand and the various types of biological soil crusts was less than that of rainfall, resulting in net soil water income. In the relative dry years (2019 and 2020), the amount of soil water expenditure covered by dominant algae and moss crusts was higher than that of rainfall, causing net soil water deficit, but opposite for bare sand. Biological soil crusts led to the imbalance of soil water budget of 0-40 cm depth and even soil water deficit in relatively dry years, which may lead to the succession of plant communities to be dominated by shallow-rooted plants in this area.