With the leaves,bark and roots of Liriodendron chinense Sarg.× L.tulipifera L.as experiment materials,the ultrasonic-assisted extraction conditions of total flavonoids were optimized by response surface Box-Behnk...With the leaves,bark and roots of Liriodendron chinense Sarg.× L.tulipifera L.as experiment materials,the ultrasonic-assisted extraction conditions of total flavonoids were optimized by response surface Box-Behnken test design.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from the leaves of L.chinense Sarg.× L.tulipifera L.;ultrasonic temperature and liquid-to-solid ratio had an interaction on the extraction amount of flavonoids;and the optimum ultrasonic time,temperature and liquid-to-solid ratio for the extraction of flavonoids from leaves of L.chinense Sarg.× L.tulipifera L.were 19.82 min,28.60 ℃ and 9.48 ml/g,respectively.Ultrasonic time,temperature and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from L.chinense Sarg.× L.tulipifera L.;there was a significant interaction between any two of the factors,which had a significant effect on the extraction of flavonoids;and the optimum extraction parameters for flavonoids in the bark were the ultrasonic time of 33.66 min,the ultrasonic temperature at 32.85 ℃ and the liquid-to-solid ratio of 11.39 ml/g.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction of flavonoids from roots;there was a significant interaction between ultrasonic time and liquid-to-solid ratio and between ultrasonic temperature and liquid-to-solid ratio;and the optimum extraction parameters for flavonoids from the roots of L.chinense Sarg.× L.tulipifera L.were the ultrasonic time of 32.38 min,the ultrasonic temperature at 25.0 ℃ and the liquid-to-solid ratio of 8.00 ml/g.The results of the three models were stable.The models are feasible and have good application value.展开更多
L波段数字航空通信系统(L band digital aeronautical communication system,LDACS)是未来航空宽带通信重要的基础设施之一,针对LDACS信号容易受到相邻波道大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出了联合正...L波段数字航空通信系统(L band digital aeronautical communication system,LDACS)是未来航空宽带通信重要的基础设施之一,针对LDACS信号容易受到相邻波道大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出了联合正交投影干扰抑制与单快拍稀疏分解的波达方向(direction of arrival,DOA)估计方法。通过子空间投影抑制DME干扰,然后使用单快拍数据构建伪协方差矩阵,对伪协方差矩阵求高阶幂,之后进行奇异值分解,并利用约束条件求解稀疏解得到期望信号来向的估计值。所提方法使用高阶伪协方差矩阵降低了噪声影响,仅用单快拍就可以准确估计LDACS信号的入射方向。仿真结果表明,改进单快拍高级幂(improved single snapshot high order power,ISS-HOP)L1-SVD算法的估计精度优于ISS-HOP-MUSIC算法。该方法可以有效抑制DME干扰,提高OFDM接收机性能。展开更多
基金Supported by the Policy Guidance Plan of Jiangsu Province(Production and Research Cooperation)(BY2016061-27)College Students’Practice Innovation Training Program of Jiangsu Province(201811049045X)
文摘With the leaves,bark and roots of Liriodendron chinense Sarg.× L.tulipifera L.as experiment materials,the ultrasonic-assisted extraction conditions of total flavonoids were optimized by response surface Box-Behnken test design.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from the leaves of L.chinense Sarg.× L.tulipifera L.;ultrasonic temperature and liquid-to-solid ratio had an interaction on the extraction amount of flavonoids;and the optimum ultrasonic time,temperature and liquid-to-solid ratio for the extraction of flavonoids from leaves of L.chinense Sarg.× L.tulipifera L.were 19.82 min,28.60 ℃ and 9.48 ml/g,respectively.Ultrasonic time,temperature and liquid-to-solid ratio had significant effects on the extraction amount of flavonoids from L.chinense Sarg.× L.tulipifera L.;there was a significant interaction between any two of the factors,which had a significant effect on the extraction of flavonoids;and the optimum extraction parameters for flavonoids in the bark were the ultrasonic time of 33.66 min,the ultrasonic temperature at 32.85 ℃ and the liquid-to-solid ratio of 11.39 ml/g.Ultrasonic time and liquid-to-solid ratio had significant effects on the extraction of flavonoids from roots;there was a significant interaction between ultrasonic time and liquid-to-solid ratio and between ultrasonic temperature and liquid-to-solid ratio;and the optimum extraction parameters for flavonoids from the roots of L.chinense Sarg.× L.tulipifera L.were the ultrasonic time of 32.38 min,the ultrasonic temperature at 25.0 ℃ and the liquid-to-solid ratio of 8.00 ml/g.The results of the three models were stable.The models are feasible and have good application value.
文摘L波段数字航空通信系统(L band digital aeronautical communication system,LDACS)是未来航空宽带通信重要的基础设施之一,针对LDACS信号容易受到相邻波道大功率测距仪(distance measuring equipment,DME)信号干扰的问题,提出了联合正交投影干扰抑制与单快拍稀疏分解的波达方向(direction of arrival,DOA)估计方法。通过子空间投影抑制DME干扰,然后使用单快拍数据构建伪协方差矩阵,对伪协方差矩阵求高阶幂,之后进行奇异值分解,并利用约束条件求解稀疏解得到期望信号来向的估计值。所提方法使用高阶伪协方差矩阵降低了噪声影响,仅用单快拍就可以准确估计LDACS信号的入射方向。仿真结果表明,改进单快拍高级幂(improved single snapshot high order power,ISS-HOP)L1-SVD算法的估计精度优于ISS-HOP-MUSIC算法。该方法可以有效抑制DME干扰,提高OFDM接收机性能。