Q Sepharose Fast Flow(Q Sepharose F.F.) was adopted to purify the suspensions of type Ⅰ,Ⅱ,Ⅲ oral poliovaccine (OPV), which is prepared from Vero cells. After clarification and concentration by ultrafiltration,th...Q Sepharose Fast Flow(Q Sepharose F.F.) was adopted to purify the suspensions of type Ⅰ,Ⅱ,Ⅲ oral poliovaccine (OPV), which is prepared from Vero cells. After clarification and concentration by ultrafiltration,the recovery of virus infected titre may attain above 85%.Using column chromatography on Q Sepharose F.F. to purify the concentrated virus suspensions,the purified viruses attain 100% recovery of virus infectivity. Dot membrane hybrization was used to detect DNA with the probe of Vero cell genome DNA which was labeled with α P 32 dATP,the contents of residual substrate DNA was less than 100 Pg/dose. The process of downstream had no significant influence on some biological characters of purified viruses,such as virus morphology ,tumorigenicity, rct/40 character and capsid protein.This downstream reseach indicates that Q Sepharose F.F. is an ideal chromatography material for purifying OPV prepared from Vero cells.展开更多
基于模块化多电平换流器的高压柔性直流输电系统(modular multilevel converter-based high voltage direct current,MMC-HVDC)常采用双极接线方式以提高系统功率输送能力和可靠性。然而目前对于风电场经柔直外送系统的稳定性研究集中...基于模块化多电平换流器的高压柔性直流输电系统(modular multilevel converter-based high voltage direct current,MMC-HVDC)常采用双极接线方式以提高系统功率输送能力和可靠性。然而目前对于风电场经柔直外送系统的稳定性研究集中于单极接线方式,孤岛直驱风电场与采用不同双极协调控制的双极MMC-HVDC互联系统小信号稳定性问题还有待进一步探究。该文首先考虑频率耦合特性、参考系初相位和直流侧耦合特性的影响,分别建立了采用双U/f下垂控制和定U/f-P/Q控制的双极MMC-HVDC系统交流侧等效SISO阻抗模型,并详细分析了金属回线阻抗和双极间功率均分度对交流阻抗特性的影响。接着对比研究了两种协调控制中共有控制环路和特有控制环路对交流侧负电阻特性及互联系统稳定性的影响规律。最后,孤岛直驱风电场经两种双极协调控制下双极MMC-HVDC外送系统Matlab/Simulink时域仿真结果和硬件在环半实物实时仿真实验结果验证了所提出的小信号阻抗模型的精确性和稳定性分析结论的有效性。展开更多
文摘Q Sepharose Fast Flow(Q Sepharose F.F.) was adopted to purify the suspensions of type Ⅰ,Ⅱ,Ⅲ oral poliovaccine (OPV), which is prepared from Vero cells. After clarification and concentration by ultrafiltration,the recovery of virus infected titre may attain above 85%.Using column chromatography on Q Sepharose F.F. to purify the concentrated virus suspensions,the purified viruses attain 100% recovery of virus infectivity. Dot membrane hybrization was used to detect DNA with the probe of Vero cell genome DNA which was labeled with α P 32 dATP,the contents of residual substrate DNA was less than 100 Pg/dose. The process of downstream had no significant influence on some biological characters of purified viruses,such as virus morphology ,tumorigenicity, rct/40 character and capsid protein.This downstream reseach indicates that Q Sepharose F.F. is an ideal chromatography material for purifying OPV prepared from Vero cells.
文摘基于模块化多电平换流器的高压柔性直流输电系统(modular multilevel converter-based high voltage direct current,MMC-HVDC)常采用双极接线方式以提高系统功率输送能力和可靠性。然而目前对于风电场经柔直外送系统的稳定性研究集中于单极接线方式,孤岛直驱风电场与采用不同双极协调控制的双极MMC-HVDC互联系统小信号稳定性问题还有待进一步探究。该文首先考虑频率耦合特性、参考系初相位和直流侧耦合特性的影响,分别建立了采用双U/f下垂控制和定U/f-P/Q控制的双极MMC-HVDC系统交流侧等效SISO阻抗模型,并详细分析了金属回线阻抗和双极间功率均分度对交流阻抗特性的影响。接着对比研究了两种协调控制中共有控制环路和特有控制环路对交流侧负电阻特性及互联系统稳定性的影响规律。最后,孤岛直驱风电场经两种双极协调控制下双极MMC-HVDC外送系统Matlab/Simulink时域仿真结果和硬件在环半实物实时仿真实验结果验证了所提出的小信号阻抗模型的精确性和稳定性分析结论的有效性。
