In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide （AAm） and methacrylic acid （MAc） in ethanol, azo-initiators were employed with various functional gro...In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide （AAm） and methacrylic acid （MAc） in ethanol, azo-initiators were employed with various functional groups such as --COOCH3 （V- 601, dimethyl 2,2＇-azobis（isobutyrate））, --CN （V-65, 2,2＇-Azobis（2,4-diemthylvaleronitrile））, --COOH （V-501, 4,4＇-azobis（4-cyanovaleric acid）） and --NH-（VA-061, 2,2＇-azobis[2-（2-imidazolin-2-yl）propane]）, respectively. Particle size, induction time and kinetics of polymerization were investigated by the scanning electron microscopy （SEM） and gravimetry. It was observed that the polymerization parameters, such as the particle size, induction time and polymerization rate, were considerably affected by the functional groups of initiators. Besides, the monomer concentration also played important roles in the particle formation. By using V-601, the polymerization rate was strongly correlated with the total surface area of particles and the concentration of initiators. However, by using V-50 l, the polymerization rate was strongly related to WoQo, where W0 is the initial concentration of monomers and Ci,0, the initial concentration of initiators. The results indicated that the different functional groups determined the different partition types of initiators between the minimonomer droplets and the continuous phase due to the molecular interactions of initiator and monomers. V-601 was all partitioned in the continuous phase, but a part of V-65 was partitioned in the minimonomer droplets. Besides the V-501 dissolved in the continuous phase, a part of V-501 was adsorbed on the surface of minimonomer droplets. VA-061 destroyed the stability of minimonomer droplets by the formation of zwitterions with MAA.展开更多
针对当前应用于状态估计的广域测量系统(Wide Area Measurement System,WAMS)和数据监控及采集系统(Supervisory Control and Data Acquisition,SCADA)数据频率兼容问题,在分析WAMS/SCADA混合量测数据差异的基础上,提出了一种可行的解...针对当前应用于状态估计的广域测量系统(Wide Area Measurement System,WAMS)和数据监控及采集系统(Supervisory Control and Data Acquisition,SCADA)数据频率兼容问题,在分析WAMS/SCADA混合量测数据差异的基础上,提出了一种可行的解决混合量测数据频率兼容的方案。文章基于数据挖掘理念和Vondrak分区插值算法,对SCADA节点依据数据相关度划分插值区域,各分区内采用同一PMU节点的最优平滑系数进行Vondrk插值,得到WAMS测量时刻的SCADA拟量测数据,应用于无迹卡尔曼滤波(Unscented Kalman Filter,UKF)动态状态估计。该方案不仅可以增补SCADA拟量测数据,提高量测数据和状态估计精度,有效控制系统负荷快速变化时的估计误差,还可以实现系统故障前后全网母线电压波动的可观测。通过在IEEE 118节点系统上模拟日负荷变化和故障过程的仿真分析,验证了该频率兼容方案的有效性。展开更多
Ⅰ. INTRODUCTIONThe tunneling was not considered in conventional transition state theory (TST). Especially within low reaction temperature the calculation of the conventional TST can bring about obvious errors. In 197...Ⅰ. INTRODUCTIONThe tunneling was not considered in conventional transition state theory (TST). Especially within low reaction temperature the calculation of the conventional TST can bring about obvious errors. In 1979, Kuppermann in his article about TST stressed the state-to-state TST. His theory used the transmission coefficient. On the basis of Kuppermann’s theory it is not difficult to consider the tunneling.展开更多
This paper proposes a branch-independence-based reliability assessment approach for transmission systems.The approach consists of branch decoupling and state-space partition techniques.By integrating an impact-increme...This paper proposes a branch-independence-based reliability assessment approach for transmission systems.The approach consists of branch decoupling and state-space partition techniques.By integrating an impact-increment-based reliability index calculation model and the proposed branch decoupling technique,a proportion of sampled contingency states no longer need to be analyzed using the time-consuming optimal power flow(OPF)algorithm.In this way,the technique speeds up the calculation of reliability indices.Since first-order contingency states have a high probability of being sampled,we propose a state-space partition technique to replace first-order contingency state simulation with first-order contingency state enumeration.Consequently,the calculation of reliability indices is further accelerated by avoiding a large amount of repetitive OPF analyses during simulation process without affecting reliability index accuracy.The validity and applicability of our approach are verified using the IEEE 118-bus and IEEE 145-bus systems.Numerical results indicate that the proposed approach can improve computational efficiency without decreasing accuracy.展开更多
为了更好地研究类氩流体的性质,采用理论推导和数值计算方法,通过修正van der Waals方程,加入了影响因子和另外一个参数,提出了一个通用的物态方程。包含了几个已知的物态方程,通过对参数的选择,给出了较好的相图。结果表明:对于类氩流...为了更好地研究类氩流体的性质,采用理论推导和数值计算方法,通过修正van der Waals方程,加入了影响因子和另外一个参数,提出了一个通用的物态方程。包含了几个已知的物态方程,通过对参数的选择,给出了较好的相图。结果表明:对于类氩流体,由此物态方程所给出的理论结果与实验符合得很好。该研究对于研究类氩流体的一级相变具有一定的参考价值。展开更多
基金financially supported by the National Natural Science Foundation of China(No.51073035)
文摘In order to investigate the partition of initiators for quasi-static precipitation polymerization of acrylamide （AAm） and methacrylic acid （MAc） in ethanol, azo-initiators were employed with various functional groups such as --COOCH3 （V- 601, dimethyl 2,2＇-azobis（isobutyrate））, --CN （V-65, 2,2＇-Azobis（2,4-diemthylvaleronitrile））, --COOH （V-501, 4,4＇-azobis（4-cyanovaleric acid）） and --NH-（VA-061, 2,2＇-azobis[2-（2-imidazolin-2-yl）propane]）, respectively. Particle size, induction time and kinetics of polymerization were investigated by the scanning electron microscopy （SEM） and gravimetry. It was observed that the polymerization parameters, such as the particle size, induction time and polymerization rate, were considerably affected by the functional groups of initiators. Besides, the monomer concentration also played important roles in the particle formation. By using V-601, the polymerization rate was strongly correlated with the total surface area of particles and the concentration of initiators. However, by using V-50 l, the polymerization rate was strongly related to WoQo, where W0 is the initial concentration of monomers and Ci,0, the initial concentration of initiators. The results indicated that the different functional groups determined the different partition types of initiators between the minimonomer droplets and the continuous phase due to the molecular interactions of initiator and monomers. V-601 was all partitioned in the continuous phase, but a part of V-65 was partitioned in the minimonomer droplets. Besides the V-501 dissolved in the continuous phase, a part of V-501 was adsorbed on the surface of minimonomer droplets. VA-061 destroyed the stability of minimonomer droplets by the formation of zwitterions with MAA.
文摘针对当前应用于状态估计的广域测量系统(Wide Area Measurement System,WAMS)和数据监控及采集系统(Supervisory Control and Data Acquisition,SCADA)数据频率兼容问题,在分析WAMS/SCADA混合量测数据差异的基础上,提出了一种可行的解决混合量测数据频率兼容的方案。文章基于数据挖掘理念和Vondrak分区插值算法,对SCADA节点依据数据相关度划分插值区域,各分区内采用同一PMU节点的最优平滑系数进行Vondrk插值,得到WAMS测量时刻的SCADA拟量测数据,应用于无迹卡尔曼滤波(Unscented Kalman Filter,UKF)动态状态估计。该方案不仅可以增补SCADA拟量测数据,提高量测数据和状态估计精度,有效控制系统负荷快速变化时的估计误差,还可以实现系统故障前后全网母线电压波动的可观测。通过在IEEE 118节点系统上模拟日负荷变化和故障过程的仿真分析,验证了该频率兼容方案的有效性。
文摘Ⅰ. INTRODUCTIONThe tunneling was not considered in conventional transition state theory (TST). Especially within low reaction temperature the calculation of the conventional TST can bring about obvious errors. In 1979, Kuppermann in his article about TST stressed the state-to-state TST. His theory used the transmission coefficient. On the basis of Kuppermann’s theory it is not difficult to consider the tunneling.
基金supported by the China Postdoctoral Science Foundation (No.2020TQ0222)。
文摘This paper proposes a branch-independence-based reliability assessment approach for transmission systems.The approach consists of branch decoupling and state-space partition techniques.By integrating an impact-increment-based reliability index calculation model and the proposed branch decoupling technique,a proportion of sampled contingency states no longer need to be analyzed using the time-consuming optimal power flow(OPF)algorithm.In this way,the technique speeds up the calculation of reliability indices.Since first-order contingency states have a high probability of being sampled,we propose a state-space partition technique to replace first-order contingency state simulation with first-order contingency state enumeration.Consequently,the calculation of reliability indices is further accelerated by avoiding a large amount of repetitive OPF analyses during simulation process without affecting reliability index accuracy.The validity and applicability of our approach are verified using the IEEE 118-bus and IEEE 145-bus systems.Numerical results indicate that the proposed approach can improve computational efficiency without decreasing accuracy.
文摘为了更好地研究类氩流体的性质,采用理论推导和数值计算方法,通过修正van der Waals方程,加入了影响因子和另外一个参数,提出了一个通用的物态方程。包含了几个已知的物态方程,通过对参数的选择,给出了较好的相图。结果表明:对于类氩流体,由此物态方程所给出的理论结果与实验符合得很好。该研究对于研究类氩流体的一级相变具有一定的参考价值。
