A jet inner-loop bioreactor (JIBR) was used to treat synthetic sanitary sewage with low, medium and high COD load. The experimental results show that it could meet discharge standard at 20\|30 min of HRT (hydraulic re...A jet inner-loop bioreactor (JIBR) was used to treat synthetic sanitary sewage with low, medium and high COD load. The experimental results show that it could meet discharge standard at 20\|30 min of HRT (hydraulic retention time) for low COD concentration and 60\|120 min of HRT for medium and high COD concentration. The maximal COD volume loading and COD sludge loading of 27 kg\5m -3 \5d -1 and 5 kg/d per kg MLSS were acheived respectively, that were 10\|20 times higher than those of traditional wastewater treatment processes. The BOD 5 removal efficiency was more than 90% and NH + 4 —N more than 85%. The study on the activity showed that the oxygen consumption rate of the activated sludge in the JIBR was 39.13 mg\5L -1 \5h -1 , which was 1.7 times higher than that of the SBR(Sequencing Batch Reactor) and the dominant bacteria in jet inner\|loop bioreactor was Pseudomonas species.展开更多
针对微特电机驱动控制系统中,双有源桥(dual active bridge,DAB)变换器在高频调制过程中易产生较大电流应力,导致器件温升高、寿命衰减及负载扰动下系统稳定性下降等问题,本文提出一种改进型双移相优化调制策略。该方法基于双有源桥拓扑...针对微特电机驱动控制系统中,双有源桥(dual active bridge,DAB)变换器在高频调制过程中易产生较大电流应力,导致器件温升高、寿命衰减及负载扰动下系统稳定性下降等问题,本文提出一种改进型双移相优化调制策略。该方法基于双有源桥拓扑,建立双移相调制下的功率传输模型与电流应力数学模型,采用拉格朗日乘数法求解最优移相比组合,并进一步推导多功率场景下的电流应力解析表达式;在控制器设计方面,引入电感电流内环补偿机制,提高系统对电机驱动过程中负载变化的动态响应能力。MATLAB/Simulink仿真结果表明,该方法在典型微特电机负载工况下能有效降低变换器的电流应力,缩短暂态响应时间,并改善输出电压纹波,对提升微特电机控制系统的稳态与暂态性能具有良好效果,为高效能电机驱动供电模块的优化设计提供理论依据。展开更多
【目的】跟网型换流器(grid-following converter,GFL)被广泛应用于新能源并网系统。电网发生故障引起电压跌落时,系统进入低电压穿越(low voltage ride-through,LVRT)过程。传统锁相环(phase-locked loop,PLL)的二阶模型因忽略电流暂...【目的】跟网型换流器(grid-following converter,GFL)被广泛应用于新能源并网系统。电网发生故障引起电压跌落时,系统进入低电压穿越(low voltage ride-through,LVRT)过程。传统锁相环(phase-locked loop,PLL)的二阶模型因忽略电流暂态过程,难以准确描述LVRT期间系统的动态特性,导致暂态同步稳定性的提升效果受限。为此,针对对称故障场景,提出一种适用于LVRT过程的电流内环协同控制策略,以增强系统暂态同步稳定性。【方法】基于PLL四阶动态方程,结合暂态能量函数法,分析PLL输出频率突变以及电流内环与PLL耦合作用对系统暂态同步稳定性的影响,并设计相应的控制策略:根据最优阻抗比动态调整电流参考值,以抑制故障期间暂态能量累积;通过在电流内环前馈解耦项中引入频率偏差补偿机制,加速暂态能量耗散过程。两者协同作用,提升系统在LVRT期间的暂态同步稳定性。【结果】PSCAD/EMTDC对称故障时域仿真结果表明:故障瞬间PLL输出频率突变量与电网电压跌落幅值成正比,增大系统失稳风险;所提控制策略能够有效抑制故障期间PLL输出频率偏差,显著降低虚拟功角首摆幅度,缩短故障清除后系统恢复时间,在不同电网参数下均表现出良好的适应性。【结论】所提电流内环协同控制策略,能够在对称故障期间有效抑制暂态能量累积,在故障清除后加速暂态能量耗散,有效提升了GFL并网系统在此类LVRT过程中的暂态同步稳定性。展开更多
In this study the mechanical version of the three-disk Tower of London task with changes in the movements was conducted by fifteen elderly participants with concurrent articulatory suppression. Also, this executive ta...In this study the mechanical version of the three-disk Tower of London task with changes in the movements was conducted by fifteen elderly participants with concurrent articulatory suppression. Also, this executive task was conducted without verbal secondary task and the results of these two states were com- pared with each other. From this comparison, got evidences based on inner speech role in more complicated Tower of London tasks, although in general, the results suggest a more outstanding role of inner scribe in spatial planning in this executive task. Then inner speech and inner scribe roles have been described in Tower of London task applying “Baddeley and Logie” working memory model.展开更多
文摘A jet inner-loop bioreactor (JIBR) was used to treat synthetic sanitary sewage with low, medium and high COD load. The experimental results show that it could meet discharge standard at 20\|30 min of HRT (hydraulic retention time) for low COD concentration and 60\|120 min of HRT for medium and high COD concentration. The maximal COD volume loading and COD sludge loading of 27 kg\5m -3 \5d -1 and 5 kg/d per kg MLSS were acheived respectively, that were 10\|20 times higher than those of traditional wastewater treatment processes. The BOD 5 removal efficiency was more than 90% and NH + 4 —N more than 85%. The study on the activity showed that the oxygen consumption rate of the activated sludge in the JIBR was 39.13 mg\5L -1 \5h -1 , which was 1.7 times higher than that of the SBR(Sequencing Batch Reactor) and the dominant bacteria in jet inner\|loop bioreactor was Pseudomonas species.
文摘针对微特电机驱动控制系统中,双有源桥(dual active bridge,DAB)变换器在高频调制过程中易产生较大电流应力,导致器件温升高、寿命衰减及负载扰动下系统稳定性下降等问题,本文提出一种改进型双移相优化调制策略。该方法基于双有源桥拓扑,建立双移相调制下的功率传输模型与电流应力数学模型,采用拉格朗日乘数法求解最优移相比组合,并进一步推导多功率场景下的电流应力解析表达式;在控制器设计方面,引入电感电流内环补偿机制,提高系统对电机驱动过程中负载变化的动态响应能力。MATLAB/Simulink仿真结果表明,该方法在典型微特电机负载工况下能有效降低变换器的电流应力,缩短暂态响应时间,并改善输出电压纹波,对提升微特电机控制系统的稳态与暂态性能具有良好效果,为高效能电机驱动供电模块的优化设计提供理论依据。
文摘【目的】跟网型换流器(grid-following converter,GFL)被广泛应用于新能源并网系统。电网发生故障引起电压跌落时,系统进入低电压穿越(low voltage ride-through,LVRT)过程。传统锁相环(phase-locked loop,PLL)的二阶模型因忽略电流暂态过程,难以准确描述LVRT期间系统的动态特性,导致暂态同步稳定性的提升效果受限。为此,针对对称故障场景,提出一种适用于LVRT过程的电流内环协同控制策略,以增强系统暂态同步稳定性。【方法】基于PLL四阶动态方程,结合暂态能量函数法,分析PLL输出频率突变以及电流内环与PLL耦合作用对系统暂态同步稳定性的影响,并设计相应的控制策略:根据最优阻抗比动态调整电流参考值,以抑制故障期间暂态能量累积;通过在电流内环前馈解耦项中引入频率偏差补偿机制,加速暂态能量耗散过程。两者协同作用,提升系统在LVRT期间的暂态同步稳定性。【结果】PSCAD/EMTDC对称故障时域仿真结果表明:故障瞬间PLL输出频率突变量与电网电压跌落幅值成正比,增大系统失稳风险;所提控制策略能够有效抑制故障期间PLL输出频率偏差,显著降低虚拟功角首摆幅度,缩短故障清除后系统恢复时间,在不同电网参数下均表现出良好的适应性。【结论】所提电流内环协同控制策略,能够在对称故障期间有效抑制暂态能量累积,在故障清除后加速暂态能量耗散,有效提升了GFL并网系统在此类LVRT过程中的暂态同步稳定性。
文摘In this study the mechanical version of the three-disk Tower of London task with changes in the movements was conducted by fifteen elderly participants with concurrent articulatory suppression. Also, this executive task was conducted without verbal secondary task and the results of these two states were com- pared with each other. From this comparison, got evidences based on inner speech role in more complicated Tower of London tasks, although in general, the results suggest a more outstanding role of inner scribe in spatial planning in this executive task. Then inner speech and inner scribe roles have been described in Tower of London task applying “Baddeley and Logie” working memory model.
