The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reducti...The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.展开更多
为提升反辐射导引头抗干扰能力,提出一种利用辐射源到达角(Direction of Arrival,DOA)信息和K-means的聚类算法。该方法利用角度网格完成测向数据图形化,通过对当前图形斑块和理想条件下单目标斑块特征参数进行比对,实现斑块内目标数量...为提升反辐射导引头抗干扰能力,提出一种利用辐射源到达角(Direction of Arrival,DOA)信息和K-means的聚类算法。该方法利用角度网格完成测向数据图形化,通过对当前图形斑块和理想条件下单目标斑块特征参数进行比对,实现斑块内目标数量自动估计,并借助K-means算法完成目标角度估计。经仿真验证,该方法能够在目标数量未知条件下,实现目标聚类,且能够适应多个辐射源目标彼此靠近,信号脉冲测向分布彼此重叠的情况,聚类后的估计角度误差不大于系统固有误差。展开更多
基金Project supported by the National Natural Science Foundation of China(21876168)the Key Projects for Common Key Technology Innovation in Key Industries in Chongqing(cstc2016zdcy-ztzx0020-01)+1 种基金Youth Innovation Promotion Association CAS(2019376)the Graduate Innovation Project of Chongqing Technology and Business University(yjscxx201803-028-22)。
文摘The purpose of this work is to explore the effects of the introduction methods of Ce^4+and Zr^4+on the physicochemical properties,activity,and K tolerance of V2 O5-WO3/TiO2 catalyst for the selective catalytic reduction of NOx by NH3.Four different methods,namely pre-impregnation,post-impregnation,coimpregnation,and co-precipitation,were used to synthesize a series of V2 O5-WO3-TiO2-CeO2-ZrO2 catalysts.The catalysts were characterized by XRD,BET,NH3-TPD,XPS,and H2-TPR techniques.Moreover,the activity and anti-K poisoning performance were tested by an NH3-SCR model reaction.The results show that the introduction of Ce^4+and Zr^4+can improve the catalytic performance of V2O5-WO3/TiO2 catalyst,but the impregnation method cannot enhance the anti-K poisoning performance.Ce^4+and Zr^4+introduced by co-precipitation method can effectively improve the tolerance of K,which is mainly due to the incorporation of Ce^4+and Zr^4+into TiO2 lattice to form a uniform TiO2-CeO2-ZrO2 solid solution,resulting in the optimal surface acidity and redox performance,and reducing the decreases caused by Kpoisoning.Furthermore,based on the best introduction method,we further optimized the molar ratio of Ce^4+/Zr^4+,It is found that the catalyst exhibits the best anti-K poisoning performance when the molar ratio of Ce^4+/Zr^4+is 2:1.
文摘为提升反辐射导引头抗干扰能力,提出一种利用辐射源到达角(Direction of Arrival,DOA)信息和K-means的聚类算法。该方法利用角度网格完成测向数据图形化,通过对当前图形斑块和理想条件下单目标斑块特征参数进行比对,实现斑块内目标数量自动估计,并借助K-means算法完成目标角度估计。经仿真验证,该方法能够在目标数量未知条件下,实现目标聚类,且能够适应多个辐射源目标彼此靠近,信号脉冲测向分布彼此重叠的情况,聚类后的估计角度误差不大于系统固有误差。
