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三元催化剂选型与设计指南
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作者 李冬旭 罗联伟 《科技创新与应用》 2024年第31期117-120,共4页
三元催化剂(TWC)旨在同时催化发动机废气中氮氧化物(NOx)的还原以及一氧化碳(CO)和碳氢化合物(HC)的氧化。理论上,在化学计量空燃比下可以获得最佳性能。然而,由于空气和燃料估计误差以及燃料供给滞后,实现这样的条件是不可行的。为了... 三元催化剂(TWC)旨在同时催化发动机废气中氮氧化物(NOx)的还原以及一氧化碳(CO)和碳氢化合物(HC)的氧化。理论上,在化学计量空燃比下可以获得最佳性能。然而,由于空气和燃料估计误差以及燃料供给滞后,实现这样的条件是不可行的。为了补偿空燃比(AFR)的固有误差,催化剂配方中添加了储氧成分(OSC),以缓冲不需要的AFR偏差。TWC架构可以为串联封装在一起的(UF)系统,也可以分为两个单独封装的系统,分割将取决于催化剂的体积和性能要求,例如CC+UF架构使TWC元件体积的一部分更靠近排气歧管(更高的温度)以获得更好的催化剂转换性能。 展开更多
关键词 三元催化剂 储氧成分 老化规格 后处理架构 三元催化剂选型
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Long-Term Frozen Storage Impact on the Antioxidant Capacity and Chemical Composition of Sardinian Myrtle (Myrtus communis L,) Berries 被引量:2
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作者 A. Angioni M. Schirra 《Journal of Agricultural Science and Technology(B)》 2011年第8期1168-1175,共8页
The effects of frozen storage at -18 ℃ up to 6 months, on the antioxidant properties, chemical composition and other physicochemical properties of myrtle berries (Myrtus comrnunis L.) has been evaluated. Berries sh... The effects of frozen storage at -18 ℃ up to 6 months, on the antioxidant properties, chemical composition and other physicochemical properties of myrtle berries (Myrtus comrnunis L.) has been evaluated. Berries showed a good resistance to storage decay, and weight loss remained after six months in the 15% range. Results showed that frozen storage up to 6 months affect individual antocyanins content in different ways. Nevertheless the total anthocyanins content was at the end of storage higher than in fresh fruits. The antioxidant capacity calculated with 2,2-diphenyl-l-picrylhidrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) increased during storage and the calculated r2 showed a positive correlation with the total anthocyanins content. Gluconic and fumaric acid did not changed, quinic acid decreased while malic and shikimic acid increased. The total organic acid content during storage was higher than in fresh fruits causing a slight decrease in pH. Fructose and glucose increased with the same rate and the ratio fructose/glucose remained unchanged (1.06 ± 0.01), CIE L^*a^*b^* coordinates showed a shift of the colour to tawny brown after six months storage. 展开更多
关键词 Myrtle berries frozen storage chemical composition antioxidant capacity.
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