The frost-driven self-fracture of ionomer-bound carbon electrodes compromises the mechanical stability of electrochemical systems under subzero conditions.This study suggests that the mechanical degradation of ionomer...The frost-driven self-fracture of ionomer-bound carbon electrodes compromises the mechanical stability of electrochemical systems under subzero conditions.This study suggests that the mechanical degradation of ionomer-bound carbon electrodes under subfreezing conditions is primarily driven by damage within the ionomer binder phase rather than within the nanopores.This damage occurs owing to the expansion of confined water upon freezing.Reducing the size of the freezable water domains significantly enhances the mechanical robustness.Structural and mechanical analyses reveal that thermal reconfiguration effectively modifies the ionomer nanostructure,leading to an approximately 30%reduction in water uptake and improved resistance to frost-induced self-fracturing.Nanostructural analyses further confirm that crystallized packing in the ionomer binder minimizes the number of water retention sites,thereby restricting the buildup of internal stress during freezing.Consequently,the elongation of the as-prepared electrodes reduces by approximately 65%after freezing at−10℃,whereas that of the thermally reconfigured electrodes is above 90%of its initial value with minimal deterioration.These findings highlight the critical role of ionomer-phase engineering in improving the low-temperature durability of ionomer-bound carbon electrodes,providing a scalable strategy applicable to fuel cells,water electrolyzers,and next-generation energy storage systems without requiring antifreezing agents.展开更多
Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of su...Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of subfreezing temperature on freezing injury of various winter wheat cultivars at different sowing time. Three wheat cultivars, including Zhengmai 9023, Wanmai 48 and Wanmai 50, were sowed on 25 September and 5 October, respectively. Plant anatomy was applied to investi- gate the impact of subfreezing temperature on cells of three wheat cultivars, results showed that severe plasmolysis occurred in wheat sowed earlier suddenly encoun- tered subfreezing temperature without cold acclimation, compared with wheat sowed at proper sowing time. The degree of plasmolysis of different cultivars and tissues of wheat had significant differences and showed positive correlation with subfreezing temperature. Wanmai 50 had the highest cold resistance compared with Zhengmai 9023 and Wanmai 48, and there was no significant difference between Zhengmai 9023 and Wanmai 48. This study concluded that wheat cold resistance may be im- proved by adopting proper cultivars and sowing dates.展开更多
基金supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT)(Grant Nos.2022R1A2C3009087 and 2022R1F1A1073173)the Korean Institute of Energy Technology Evaluation and Planning (KETEP)+1 种基金the Ministry of Trade,Industry & Energy (MOTIE) of the Republic of Korea (Grant No. RS-2024-00394769)the research grant of Kongju National University in 2022
文摘The frost-driven self-fracture of ionomer-bound carbon electrodes compromises the mechanical stability of electrochemical systems under subzero conditions.This study suggests that the mechanical degradation of ionomer-bound carbon electrodes under subfreezing conditions is primarily driven by damage within the ionomer binder phase rather than within the nanopores.This damage occurs owing to the expansion of confined water upon freezing.Reducing the size of the freezable water domains significantly enhances the mechanical robustness.Structural and mechanical analyses reveal that thermal reconfiguration effectively modifies the ionomer nanostructure,leading to an approximately 30%reduction in water uptake and improved resistance to frost-induced self-fracturing.Nanostructural analyses further confirm that crystallized packing in the ionomer binder minimizes the number of water retention sites,thereby restricting the buildup of internal stress during freezing.Consequently,the elongation of the as-prepared electrodes reduces by approximately 65%after freezing at−10℃,whereas that of the thermally reconfigured electrodes is above 90%of its initial value with minimal deterioration.These findings highlight the critical role of ionomer-phase engineering in improving the low-temperature durability of ionomer-bound carbon electrodes,providing a scalable strategy applicable to fuel cells,water electrolyzers,and next-generation energy storage systems without requiring antifreezing agents.
基金Supported by National Science and Technology Support Program of China(2011BAD16B06,2012BAD04B09)~~
文摘Freezing injury is one of the major disasters for the production of winter wheat in the North China Plain, which leads to a significant decrease of wheat yield. This study was conducted to investigate the impact of subfreezing temperature on freezing injury of various winter wheat cultivars at different sowing time. Three wheat cultivars, including Zhengmai 9023, Wanmai 48 and Wanmai 50, were sowed on 25 September and 5 October, respectively. Plant anatomy was applied to investi- gate the impact of subfreezing temperature on cells of three wheat cultivars, results showed that severe plasmolysis occurred in wheat sowed earlier suddenly encoun- tered subfreezing temperature without cold acclimation, compared with wheat sowed at proper sowing time. The degree of plasmolysis of different cultivars and tissues of wheat had significant differences and showed positive correlation with subfreezing temperature. Wanmai 50 had the highest cold resistance compared with Zhengmai 9023 and Wanmai 48, and there was no significant difference between Zhengmai 9023 and Wanmai 48. This study concluded that wheat cold resistance may be im- proved by adopting proper cultivars and sowing dates.
