The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa(aphids and thrips)were compared in three sites across China’s alfalfa belt.In addition,the persistence of ...The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa(aphids and thrips)were compared in three sites across China’s alfalfa belt.In addition,the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.Efficacy varied among the different biological and chemical insecticides.The chemical insecticides were significantly more effective than biopesticides in a short time-frame.The efficacy period of biopesticides was significantly longer than that of chemical insecticides,and the corrected mortality rate of aphids in all regions was above 50%at 14 days after application.The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.Compared with chemical insecticides,the yield of alfalfa hay was higher in the biopesticides treatments.Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China,and for reducing chemical insecticide usage and improving forage quality.展开更多
针对语音通信系统中由于干扰、音频源不稳定等因素导致的接收端语音突变或响度不一致的问题,提出一种变步长最小均方误差自适应增益控制(VSSLMS-AGC,variable step size least mean square-adaptive gain control)新方案。该方案首先利...针对语音通信系统中由于干扰、音频源不稳定等因素导致的接收端语音突变或响度不一致的问题,提出一种变步长最小均方误差自适应增益控制(VSSLMS-AGC,variable step size least mean square-adaptive gain control)新方案。该方案首先利用指数加权移动平均记录历史梯度信息,以此来调节最小均方误差算法的步长,使算法收敛速度更快,稳态误差更小;然后将变步长思想运用到自动增益控制中,确保能够自适应地调节语音增益值,使原先幅值不一的音频信号输出范围恒定且不失原有的特性,降低语音落差,改善听觉感受。展开更多
基金supported by China Agriculture Research System of MOF and MARA(CARS-34).
文摘The efficacies of biological and conventional chemical insecticides against two major insect pests of alfalfa(aphids and thrips)were compared in three sites across China’s alfalfa belt.In addition,the persistence of the residues of chemical insecticides in alfalfa and their influence on the quality of alfalfa hay were examined.Efficacy varied among the different biological and chemical insecticides.The chemical insecticides were significantly more effective than biopesticides in a short time-frame.The efficacy period of biopesticides was significantly longer than that of chemical insecticides,and the corrected mortality rate of aphids in all regions was above 50%at 14 days after application.The analysis of pesticide residues showed that the residual doses of all the pesticides were within the allowed ranges after the safe period.The acid detergent fiber and neutral detergent fiber contents in alfalfa hay were higher and the protein content was lower in chemical insecticide treatments than in biopesticide treatments in Hebei.The relative feeding value of alfalfa hay treated with Metarhizium anisopliae IPP330189 was the highest among the treatments.Compared with chemical insecticides,the yield of alfalfa hay was higher in the biopesticides treatments.Biopesticides show a stronger control effect on insect populations and also a better improvement in the quality of alfalfa hay than chemical insecticides.This study provides a basis for exploring and developing a comprehensive control regime for alfalfa insect pests in the different alfalfa-growing regions in China,and for reducing chemical insecticide usage and improving forage quality.
文摘针对语音通信系统中由于干扰、音频源不稳定等因素导致的接收端语音突变或响度不一致的问题,提出一种变步长最小均方误差自适应增益控制(VSSLMS-AGC,variable step size least mean square-adaptive gain control)新方案。该方案首先利用指数加权移动平均记录历史梯度信息,以此来调节最小均方误差算法的步长,使算法收敛速度更快,稳态误差更小;然后将变步长思想运用到自动增益控制中,确保能够自适应地调节语音增益值,使原先幅值不一的音频信号输出范围恒定且不失原有的特性,降低语音落差,改善听觉感受。
