P-arsanilic acid(p-ASA),as a kind of organoarsenic feed additive,has been widely used in poultry and swine breeding.However,it has caused the arsenic pollution around the farm.Currently data shows humic acid(HA)is clo...P-arsanilic acid(p-ASA),as a kind of organoarsenic feed additive,has been widely used in poultry and swine breeding.However,it has caused the arsenic pollution around the farm.Currently data shows humic acid(HA)is closely to the migration and transformation of p-ASA.Therefore,the interaction between p-ASA and HA was investigated by using the method of fluorescence quenching titration.The association constant changed from2.74 to 4.88 L·mol-1at a p H varying from 5 to 9 and reached the maximum at p H 7.In addition,log K varied from4.15 to 5.02 L·mol-1when the temperature increased from 15℃to 35℃.The log K increased with an increase in the concentration of HA.The dominant mechanism between p-ASA and HA is static quenching.The primary interaction force was likely the hydrogen bond,and the binding behavior occurred on the As-O stretch of p-ASA and the carboxylic acid C=O stretch of HA.The results showed that dissolved organic matters could affect the fate and biogeochemical cycling of organoarsenic pharmaceuticals in aquatic ecosystems.展开更多
为解决软件无线电(Software Defined Radio,SDR)中采样后信号混叠问题,提出了一种改进的相位调整滤波算法。依托具备可调时间延迟的二阶射频带通采样前端,设计了一种支持多分点分段滤波的抗混叠滤波器,可以根据实际需求灵活设置多个频...为解决软件无线电(Software Defined Radio,SDR)中采样后信号混叠问题,提出了一种改进的相位调整滤波算法。依托具备可调时间延迟的二阶射频带通采样前端,设计了一种支持多分点分段滤波的抗混叠滤波器,可以根据实际需求灵活设置多个频率分点,从而实现针对不同频段的精确滤波。通过在MATLAB SIMULINK中进行仿真验证,该方法相比同类方法的滤波器抑制效果更佳,达到38 dB以上,并能有效滤除所需信号而不影响其他信号的完整性,简化了接收前端,具备较强的灵活性和适应性,能够更好地支持未来的通信技术和高密度通信连接。展开更多
基金National Natural Science Foundation of China(41373111)
文摘P-arsanilic acid(p-ASA),as a kind of organoarsenic feed additive,has been widely used in poultry and swine breeding.However,it has caused the arsenic pollution around the farm.Currently data shows humic acid(HA)is closely to the migration and transformation of p-ASA.Therefore,the interaction between p-ASA and HA was investigated by using the method of fluorescence quenching titration.The association constant changed from2.74 to 4.88 L·mol-1at a p H varying from 5 to 9 and reached the maximum at p H 7.In addition,log K varied from4.15 to 5.02 L·mol-1when the temperature increased from 15℃to 35℃.The log K increased with an increase in the concentration of HA.The dominant mechanism between p-ASA and HA is static quenching.The primary interaction force was likely the hydrogen bond,and the binding behavior occurred on the As-O stretch of p-ASA and the carboxylic acid C=O stretch of HA.The results showed that dissolved organic matters could affect the fate and biogeochemical cycling of organoarsenic pharmaceuticals in aquatic ecosystems.
文摘为解决软件无线电(Software Defined Radio,SDR)中采样后信号混叠问题,提出了一种改进的相位调整滤波算法。依托具备可调时间延迟的二阶射频带通采样前端,设计了一种支持多分点分段滤波的抗混叠滤波器,可以根据实际需求灵活设置多个频率分点,从而实现针对不同频段的精确滤波。通过在MATLAB SIMULINK中进行仿真验证,该方法相比同类方法的滤波器抑制效果更佳,达到38 dB以上,并能有效滤除所需信号而不影响其他信号的完整性,简化了接收前端,具备较强的灵活性和适应性,能够更好地支持未来的通信技术和高密度通信连接。
