为探明不同深度的基质含水率变化规律,使用干燥法分别对多个EC5型传感器进行校准,并将4个传感器分别放置垂向距滴头5、10、15、20 cm 4个不同深度处,测量不同滴头流量及滴灌量条件下垂向基质含水率的变化,建立了不同深度基质含水率预测...为探明不同深度的基质含水率变化规律,使用干燥法分别对多个EC5型传感器进行校准,并将4个传感器分别放置垂向距滴头5、10、15、20 cm 4个不同深度处,测量不同滴头流量及滴灌量条件下垂向基质含水率的变化,建立了不同深度基质含水率预测模型。试验结果表明,在滴灌开始后第1层(距滴头5 cm处)基质含水率最先上升并迅速达到较高水平,滴灌停止后水分将快速扩散至更深基质层,其含水率可提升至根系易利用水平(25.3%及以上),水分快速运移时间持续1 h左右,随着初始基质含水率的降低,在相同滴头流量及灌溉量条件下,水分在垂直方向的运移程度更深,将第1层基质初始含水率、滴灌时间、预测时间、预测层高度差、滴头流量作为输入,利用遗传算法优化的BP神经网络算法与随机森林回归算法(RFR),建立滴灌下基质不同深度含水率预测模型。将试验所预测的滴灌后基质含水率与实际测量的不同深度基质含水率进行对比分析,并对不同预测深度的预测结果进行误差分析,结果表明GABP预测模型及RFR预测模型的R2分别为0.8664、0.9465,即RFR算法建立的预测模型更加精确,并且预测深度越接近于第1层基质预测结果越准确。展开更多
Nano or micro-scale particles are considered as a zero-dimensional material,and their shape is difficult to control.Here the crystal-like microparticles are formed,and the existence criterion of crystal-like low dimen...Nano or micro-scale particles are considered as a zero-dimensional material,and their shape is difficult to control.Here the crystal-like microparticles are formed,and the existence criterion of crystal-like low dimensional materials is established.The hydrothermal method is used to fabricate copper-1,3,5-phenyltricarboxylate(Cu-BTC)microparticles,which have a regular geometric shape with regular triangle,quadrangle and hexagon.The benzene ring and carboxyls(-COOH)attached to the benzene ring form two basic molecular structures of[Cu3(BTC)2]n,which play an essential role in the construction of a three-dimensional crystal-like structure.展开更多
文摘为探明不同深度的基质含水率变化规律,使用干燥法分别对多个EC5型传感器进行校准,并将4个传感器分别放置垂向距滴头5、10、15、20 cm 4个不同深度处,测量不同滴头流量及滴灌量条件下垂向基质含水率的变化,建立了不同深度基质含水率预测模型。试验结果表明,在滴灌开始后第1层(距滴头5 cm处)基质含水率最先上升并迅速达到较高水平,滴灌停止后水分将快速扩散至更深基质层,其含水率可提升至根系易利用水平(25.3%及以上),水分快速运移时间持续1 h左右,随着初始基质含水率的降低,在相同滴头流量及灌溉量条件下,水分在垂直方向的运移程度更深,将第1层基质初始含水率、滴灌时间、预测时间、预测层高度差、滴头流量作为输入,利用遗传算法优化的BP神经网络算法与随机森林回归算法(RFR),建立滴灌下基质不同深度含水率预测模型。将试验所预测的滴灌后基质含水率与实际测量的不同深度基质含水率进行对比分析,并对不同预测深度的预测结果进行误差分析,结果表明GABP预测模型及RFR预测模型的R2分别为0.8664、0.9465,即RFR算法建立的预测模型更加精确,并且预测深度越接近于第1层基质预测结果越准确。
基金National Natural Science Foundation of China(No.11372205)。
文摘Nano or micro-scale particles are considered as a zero-dimensional material,and their shape is difficult to control.Here the crystal-like microparticles are formed,and the existence criterion of crystal-like low dimensional materials is established.The hydrothermal method is used to fabricate copper-1,3,5-phenyltricarboxylate(Cu-BTC)microparticles,which have a regular geometric shape with regular triangle,quadrangle and hexagon.The benzene ring and carboxyls(-COOH)attached to the benzene ring form two basic molecular structures of[Cu3(BTC)2]n,which play an essential role in the construction of a three-dimensional crystal-like structure.
