摘要
通过动态机械分析仪(DMA)对水稻种子的热力学和流变特性进行了研究,并对种子的蠕变和应力松弛特性进行了数学模拟分析。研究表明,在DMA的加热过程中,可以明显检测到水稻种子的热转变区域,并从加热过程中样品的长度变化可得出随着含水率从(11.3±0.23)%增加到(24.3±0.47)%,样品玻璃化转变温度从(71.37±2.76)℃降低到(31.84±2.51)℃。线性模型和Gordon-Taylor公式模型能很好地模拟水稻种子的玻璃化转变温度和含水率之间的关系,并且具有很高的决定系数(R2>0.98)。通过水稻种子的蠕变和应力松弛特性分析表明,五元件开尔文模型和三元件麦克斯韦模型可以很好地模拟样品的蠕变和应力松弛特性,样品含水率和长度共同显著影响样品的蠕变特性,而只有含水率显著影响样品的应力松弛特性。
The thermal dynamical and rheological properties as well as mathematical simulation analysis of rice seeds were studied by dynamic mechanical analysis（ DMA）. A long grain hybrid rice variety（ Jinyou 974） grown in Hunan Province of China was used in this investigation. The results showed that the thermal transition was observed obviously and the length change of rice seeds with a loaded constant force along the major axis direction was detected during temperature scanning. The glass transition temperature decreased from（ 71. 37 ± 2. 76） ℃ to（ 31. 84 ± 2. 51） ℃ with moisture content increased from（ 11. 3 ± 0. 23） % to（ 24. 3 ± 0. 47） %. Both the linear function and Gordon-Taylor model can adequately represent the variation of glass transition temperature with moisture content（ R^2〉0. 98）. In order to do more in-depth study of thermal dynamical properties of rice seeds,the creep and stress relaxation characteristics were tested on the basis of temperature scanning. 5-element Kelvin model and3-element Maxwell model could match the creep and relaxation behavior of rice seeds well and the results showed that the creep behavior was significantly affected by its moisture content and length,while the relaxation behavior was only influenced by its moisture content. These indicated that there would be unavoidable stress cracks because of the influence of creep and relaxation during storage and transportation process.
出处
《农业机械学报》
EI
CAS
CSCD
北大核心
2015年第7期245-250,共6页
Transactions of the Chinese Society for Agricultural Machinery
基金
中央高校基本科研业务费专项资金资助项目(2013XJ021)
公益性行业(农业)科研专项经费资助项目(201003077)
国家大学生科学研究与创业行动计划资助项目(201410019071)
