稻谷籽粒内部水分扩散的快慢决定了干燥速率。本文基于Logarithmic方程,建立稻谷水分传递动力学模型,并分析热风温度(40、50、60、70℃)和风速(0.3、0.4、0.5 m/s)对稻谷(湿基水分含量23.4%)有效水分扩散系数和扩散活化能的影响。结果表...稻谷籽粒内部水分扩散的快慢决定了干燥速率。本文基于Logarithmic方程,建立稻谷水分传递动力学模型,并分析热风温度(40、50、60、70℃)和风速(0.3、0.4、0.5 m/s)对稻谷(湿基水分含量23.4%)有效水分扩散系数和扩散活化能的影响。结果表明:随着干燥温度和风速的上升,稻谷干燥速率提高,同时对应的有效水分扩散系数越大,分别为5.123×10-12~2.141×10-11m^2/s;扩散活化能从32.94 k J/mol增加至36.30 k J/mol;对比常用的5种谷物干燥模型发现,Logarithmic模型对稻谷薄层干燥的拟合度较好,R2>0.997,RMSE<2.810×10^(-3),同时该模型模拟得出的有效水分扩散系数与实际差值均低于3.8×10^(-13)m^2/s,扩散活化能均低于2.53 k J/mol,与实际值基本吻合。展开更多
The chronoampermetry was used to measure the Fe3+ diffusion coefficient of 0.031 16 mol/kg of FeCl3 in the ionic liquid, BPBF4, at GC working electrode referred to Al/Al3+ and at different scan rates over the temperat...The chronoampermetry was used to measure the Fe3+ diffusion coefficient of 0.031 16 mol/kg of FeCl3 in the ionic liquid, BPBF4, at GC working electrode referred to Al/Al3+ and at different scan rates over the temperature range from 293.15 to 343.15 K. Since the Fe3+ reduction reaction is a reversible process with one transfer electron, according to Cottrell′s equation, the values of diffusion coefficient of Fe3+ at different temperatures were estimated. As temperature increases, the values of the diffusion coefficient also increase owing to the diminution of the BPBF4 viscosity. The values of diffusion coefficient were fitted with the method of least-square according to Arrenius′ equation, and value of diffusion activation energy of Fe3+, ED=49.5 kJ/mol, was obtained from Arrenius′ slope.展开更多
实验采用两步法对玻璃进行离子交换,主要研究经过不同第二步离子交换时间后的玻璃在性能上的区别。本文测试了K+、Na+的分布情况,表面应力及应力深度,弯曲强度,弹性模量,并计算出K+、Na+的离子扩散系数和K+、Na+的扩散活化能。结果表明...实验采用两步法对玻璃进行离子交换,主要研究经过不同第二步离子交换时间后的玻璃在性能上的区别。本文测试了K+、Na+的分布情况,表面应力及应力深度,弯曲强度,弹性模量,并计算出K+、Na+的离子扩散系数和K+、Na+的扩散活化能。结果表明:经过两步离子交换后,应力层深度、Weibull模量和弹性模量会增加,表面应力和弯曲强度会减小。第二步离子交换温度为340℃,第二步离子交换时间从0.1 h到3 h,在第二步离子交换时间为0.5 h时,K+扩散系数为0.43×10-15m2/s,K+扩散活化能为144.00 k J/mol,Na+扩散系数为0.30×10-15m2/s,Na+扩散活化能为145.93 k J/mol,比较有利于K+、Na+的扩散。总体上,Na+的扩散系数大于K+的扩散系数,Na+的扩散活化能小于K+的扩散活化能。展开更多
文摘稻谷籽粒内部水分扩散的快慢决定了干燥速率。本文基于Logarithmic方程,建立稻谷水分传递动力学模型,并分析热风温度(40、50、60、70℃)和风速(0.3、0.4、0.5 m/s)对稻谷(湿基水分含量23.4%)有效水分扩散系数和扩散活化能的影响。结果表明:随着干燥温度和风速的上升,稻谷干燥速率提高,同时对应的有效水分扩散系数越大,分别为5.123×10-12~2.141×10-11m^2/s;扩散活化能从32.94 k J/mol增加至36.30 k J/mol;对比常用的5种谷物干燥模型发现,Logarithmic模型对稻谷薄层干燥的拟合度较好,R2>0.997,RMSE<2.810×10^(-3),同时该模型模拟得出的有效水分扩散系数与实际差值均低于3.8×10^(-13)m^2/s,扩散活化能均低于2.53 k J/mol,与实际值基本吻合。
文摘The chronoampermetry was used to measure the Fe3+ diffusion coefficient of 0.031 16 mol/kg of FeCl3 in the ionic liquid, BPBF4, at GC working electrode referred to Al/Al3+ and at different scan rates over the temperature range from 293.15 to 343.15 K. Since the Fe3+ reduction reaction is a reversible process with one transfer electron, according to Cottrell′s equation, the values of diffusion coefficient of Fe3+ at different temperatures were estimated. As temperature increases, the values of the diffusion coefficient also increase owing to the diminution of the BPBF4 viscosity. The values of diffusion coefficient were fitted with the method of least-square according to Arrenius′ equation, and value of diffusion activation energy of Fe3+, ED=49.5 kJ/mol, was obtained from Arrenius′ slope.
文摘实验采用两步法对玻璃进行离子交换,主要研究经过不同第二步离子交换时间后的玻璃在性能上的区别。本文测试了K+、Na+的分布情况,表面应力及应力深度,弯曲强度,弹性模量,并计算出K+、Na+的离子扩散系数和K+、Na+的扩散活化能。结果表明:经过两步离子交换后,应力层深度、Weibull模量和弹性模量会增加,表面应力和弯曲强度会减小。第二步离子交换温度为340℃,第二步离子交换时间从0.1 h到3 h,在第二步离子交换时间为0.5 h时,K+扩散系数为0.43×10-15m2/s,K+扩散活化能为144.00 k J/mol,Na+扩散系数为0.30×10-15m2/s,Na+扩散活化能为145.93 k J/mol,比较有利于K+、Na+的扩散。总体上,Na+的扩散系数大于K+的扩散系数,Na+的扩散活化能小于K+的扩散活化能。
