Ionic liquids predominantly consist of ionic species[1]and have low melting points[2]usually less than 373 K.They were widely used in organic syn-thesis as green solvents or catalysts[3,4].Recently,Cooper et al[5]repo...Ionic liquids predominantly consist of ionic species[1]and have low melting points[2]usually less than 373 K.They were widely used in organic syn-thesis as green solvents or catalysts[3,4].Recently,Cooper et al[5]reported the preparation of an AEL type aluminophosphate molecular sieve using 1-ethyl-3-methylimidazolium bromide([emim]Br)ionic liq-uid as both the solvent and template.They named the novel attractive procedure ionothermal synthesis to distinguish it from the hydrothermal process.The AEL type aluminophosphate molecular sieve has no acidic sites because of its electrically neutral struc-ture[6].However,introducing Si species to substitute P in the framework will impart mild acidity to the AEL type molecular sieve and make it active for a va-riety of heterogeneous acidic catalytic reactions such as the hydroisomerization of alkane[7.8].In this work,Si species were introduced into the synthesis mixture and the silicoaluminophosphate molecular sieve with AEl structure was ionothermally synthe-sized.Meanwhile,the effect of Si species amount on the product properties was investigated.展开更多
针对过程复杂且结构未知的对象,在保证模型有效性的前提下,根据数据信息构建简单模型来简化控制器的求解是亟待解决的问题。以受控自回归模型为例,提出一种基于修正最小角回归算法的稀疏辨识方法。首先将系统模型转化为过参数化的高维...针对过程复杂且结构未知的对象,在保证模型有效性的前提下,根据数据信息构建简单模型来简化控制器的求解是亟待解决的问题。以受控自回归模型为例,提出一种基于修正最小角回归算法的稀疏辨识方法。首先将系统模型转化为过参数化的高维稀疏模型,然后将最小角回归算法用于稀疏系统辨识,并提出绝对角度停止准则,使算法经过少量的迭代即可获得模型的稀疏参数估计,并同时获得有效的时滞和阶次估计。结合辨识得到的受控自回归模型,引入一种基于指定相位点频率和增益的比例-积分-微分(proportional integral derivative,PID)控制器。数值仿真和平衡机器人的姿态控制仿真表明,该稀疏辨识算法在低数据量下具有较高的辨识精度,建立的模型具有较好的泛化性能,控制器具有良好的控制效果。展开更多
文摘Ionic liquids predominantly consist of ionic species[1]and have low melting points[2]usually less than 373 K.They were widely used in organic syn-thesis as green solvents or catalysts[3,4].Recently,Cooper et al[5]reported the preparation of an AEL type aluminophosphate molecular sieve using 1-ethyl-3-methylimidazolium bromide([emim]Br)ionic liq-uid as both the solvent and template.They named the novel attractive procedure ionothermal synthesis to distinguish it from the hydrothermal process.The AEL type aluminophosphate molecular sieve has no acidic sites because of its electrically neutral struc-ture[6].However,introducing Si species to substitute P in the framework will impart mild acidity to the AEL type molecular sieve and make it active for a va-riety of heterogeneous acidic catalytic reactions such as the hydroisomerization of alkane[7.8].In this work,Si species were introduced into the synthesis mixture and the silicoaluminophosphate molecular sieve with AEl structure was ionothermally synthe-sized.Meanwhile,the effect of Si species amount on the product properties was investigated.
文摘针对过程复杂且结构未知的对象,在保证模型有效性的前提下,根据数据信息构建简单模型来简化控制器的求解是亟待解决的问题。以受控自回归模型为例,提出一种基于修正最小角回归算法的稀疏辨识方法。首先将系统模型转化为过参数化的高维稀疏模型,然后将最小角回归算法用于稀疏系统辨识,并提出绝对角度停止准则,使算法经过少量的迭代即可获得模型的稀疏参数估计,并同时获得有效的时滞和阶次估计。结合辨识得到的受控自回归模型,引入一种基于指定相位点频率和增益的比例-积分-微分(proportional integral derivative,PID)控制器。数值仿真和平衡机器人的姿态控制仿真表明,该稀疏辨识算法在低数据量下具有较高的辨识精度,建立的模型具有较好的泛化性能,控制器具有良好的控制效果。
