A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power...A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power series expansion developed in resolving the so-called Grandi’s paradox. Comparisons with accurate tabulated values for well-known cases such as the error function are presented using the expansions truncated at various orders.展开更多
串联同步开关电感(Series Synchronous Switch Harvesting on Inductor,S-SSHI)电路输出功率高整流电压范围窄,而同步电荷提取(Synchronous Electric Charge Extraction,SECE)电路则输出功率低整流电压范围宽。提出了一种基于S-SSHI和S...串联同步开关电感(Series Synchronous Switch Harvesting on Inductor,S-SSHI)电路输出功率高整流电压范围窄,而同步电荷提取(Synchronous Electric Charge Extraction,SECE)电路则输出功率低整流电压范围宽。提出了一种基于S-SSHI和SECE混合的压电阵列能量俘获接口电路,以实现整流器峰值输出功率和最佳整流电压范围之间的平衡。所提出的电路去除了整流桥结构,而采用简单的无源峰值检测器设计,且可以在任意相位差(0~2π)下从多个压电换能器中提取能量。仿真和实验结果表明,所提出的电路具有较高的输出功率和较宽的整流电压范围,与多输入全桥整流器相比,最大输出功率提升了3.04倍。展开更多
为提高非平稳响应信号瞬时频率的识别效果,提出基于滑动窗宽优化的局部最大同步挤压广义S变换(local maximum synchrosqueezing generalized S-transform,LMSSGST)。该方法首先对非平稳响应信号进行广义S变换获得相应的时频系数;其次,...为提高非平稳响应信号瞬时频率的识别效果,提出基于滑动窗宽优化的局部最大同步挤压广义S变换(local maximum synchrosqueezing generalized S-transform,LMSSGST)。该方法首先对非平稳响应信号进行广义S变换获得相应的时频系数;其次,利用该响应信号的功率谱密度特征曲线确定局部最大同步挤压算子中滑动窗的宽度;再次,通过局部最大同步挤压算子进行时频重排;最后,采用模极大值改进算法提取瞬时频率曲线。通过两个数值算例、一个滑动窗宽参数分析和一个时变拉索试验验证了所提方法的有效性,研究结果表明:利用功率谱密度特征曲线能够有效确定滑动窗的窗宽和模极大值算法的提取范围。相比局部最大同步挤压变换算法,基于滑动窗宽优化的LMSSGST具有更佳的瞬时频率识别效果。展开更多
电源网络S参数与芯片电源模型(Chip Power Module,CPM)级联可实现电源时域噪声仿真,完成电源完整性设计签核。当下部分仿真工具在AC阻抗优化过程中导出的S参数存在低频段无法覆盖的问题,影响时域纹波仿真精度,如果重新对S参数进行提取,...电源网络S参数与芯片电源模型(Chip Power Module,CPM)级联可实现电源时域噪声仿真,完成电源完整性设计签核。当下部分仿真工具在AC阻抗优化过程中导出的S参数存在低频段无法覆盖的问题,影响时域纹波仿真精度,如果重新对S参数进行提取,又会增加仿真时间降低仿真效率。针对AC阻抗优化过程中导出的S参数无法覆盖低频段的问题,提出了一种电源网络S参数低频段拓展方法,结合电压调节模块(Voltage Regulator Module,VRM)的R-L模型,推导出低频段的S参数可以借用抽取的S参数中最低频点处的S参数实现低频段S参数的拓展。仿真和实验结果表明,通过对低频段S参数进行拓展,电源时域纹波噪声仿真的精度提升31%。同时,低频段的S参数直接借用已抽取的S参数中低频点的数值无须重复提取,在8 GB内存的配置下,仿真时间节约14%左右,提高了仿真效率。展开更多
In the year of 1768,the country was sent into a nation wide panic by a sorcery case named"soul stealing"in China,to which the emperor,officials and civilians at that time all responded differently.Based on t...In the year of 1768,the country was sent into a nation wide panic by a sorcery case named"soul stealing"in China,to which the emperor,officials and civilians at that time all responded differently.Based on the"soul stealing"case,this paper gives an analysis of the political environment and the bureaucratic system to explore the motives driven by power involved in the proceedings of the case,and in doing so the paper attempts to provide insights into the implications of the ancient power system that makes possible the abuse of authority.展开更多
为了提高电能质量扰动(power quality disturbance,PQD)识别结果的准确性,笔者提出一种基于改进灰狼优化算法(improved grey wolf optimization,IGWO)优化最小二乘支持向量机(least squares support vector machine,LSSVM)的PQD识别方...为了提高电能质量扰动(power quality disturbance,PQD)识别结果的准确性,笔者提出一种基于改进灰狼优化算法(improved grey wolf optimization,IGWO)优化最小二乘支持向量机(least squares support vector machine,LSSVM)的PQD识别方法。通过采用收敛因数指数调整、自适应位移和权重动态修订等措施对灰狼优化算法进行改进,得到IGWO算法;以PQD信号的9个特征量为支持向量、7种PQD类型为输出量,利用IGWO算法寻找LSSVM的最优参数,建立基于IGWO-LSSVM的PQD识别模型并进行仿真分析,且与其他模型的识别结果进行对比。结果表明,相比算例中列出的几种对比模型,IGWO-LSSVM模型识别结果的正确率更高,验证了所提PQD识别方法的有效性和实用性。展开更多
This paper introduces the system structure and work principle of the upgraded real time information system in Wangting Power Plant, and then expounds the realization way and function features of this system on B/S co...This paper introduces the system structure and work principle of the upgraded real time information system in Wangting Power Plant, and then expounds the realization way and function features of this system on B/S computing mode. The results of field application show the new system has good capability, reliability and expandability.展开更多
文摘A generalized form of the error function, Gp(x)=pΓ(1/p)∫0xe−tpdt, which is directly associated with the gamma function, is evaluated for arbitrary real values of p>1and 0x≤+∞by employing a fast-converging power series expansion developed in resolving the so-called Grandi’s paradox. Comparisons with accurate tabulated values for well-known cases such as the error function are presented using the expansions truncated at various orders.
文摘串联同步开关电感(Series Synchronous Switch Harvesting on Inductor,S-SSHI)电路输出功率高整流电压范围窄,而同步电荷提取(Synchronous Electric Charge Extraction,SECE)电路则输出功率低整流电压范围宽。提出了一种基于S-SSHI和SECE混合的压电阵列能量俘获接口电路,以实现整流器峰值输出功率和最佳整流电压范围之间的平衡。所提出的电路去除了整流桥结构,而采用简单的无源峰值检测器设计,且可以在任意相位差(0~2π)下从多个压电换能器中提取能量。仿真和实验结果表明,所提出的电路具有较高的输出功率和较宽的整流电压范围,与多输入全桥整流器相比,最大输出功率提升了3.04倍。
文摘为提高非平稳响应信号瞬时频率的识别效果,提出基于滑动窗宽优化的局部最大同步挤压广义S变换(local maximum synchrosqueezing generalized S-transform,LMSSGST)。该方法首先对非平稳响应信号进行广义S变换获得相应的时频系数;其次,利用该响应信号的功率谱密度特征曲线确定局部最大同步挤压算子中滑动窗的宽度;再次,通过局部最大同步挤压算子进行时频重排;最后,采用模极大值改进算法提取瞬时频率曲线。通过两个数值算例、一个滑动窗宽参数分析和一个时变拉索试验验证了所提方法的有效性,研究结果表明:利用功率谱密度特征曲线能够有效确定滑动窗的窗宽和模极大值算法的提取范围。相比局部最大同步挤压变换算法,基于滑动窗宽优化的LMSSGST具有更佳的瞬时频率识别效果。
基金supported by the Key Discipline of Administrative Law Project of Shanghai University of Political Science and Law at Colleges and Universities sponsored by the Central Finance
文摘In the year of 1768,the country was sent into a nation wide panic by a sorcery case named"soul stealing"in China,to which the emperor,officials and civilians at that time all responded differently.Based on the"soul stealing"case,this paper gives an analysis of the political environment and the bureaucratic system to explore the motives driven by power involved in the proceedings of the case,and in doing so the paper attempts to provide insights into the implications of the ancient power system that makes possible the abuse of authority.
文摘为了提高电能质量扰动(power quality disturbance,PQD)识别结果的准确性,笔者提出一种基于改进灰狼优化算法(improved grey wolf optimization,IGWO)优化最小二乘支持向量机(least squares support vector machine,LSSVM)的PQD识别方法。通过采用收敛因数指数调整、自适应位移和权重动态修订等措施对灰狼优化算法进行改进,得到IGWO算法;以PQD信号的9个特征量为支持向量、7种PQD类型为输出量,利用IGWO算法寻找LSSVM的最优参数,建立基于IGWO-LSSVM的PQD识别模型并进行仿真分析,且与其他模型的识别结果进行对比。结果表明,相比算例中列出的几种对比模型,IGWO-LSSVM模型识别结果的正确率更高,验证了所提PQD识别方法的有效性和实用性。
文摘This paper introduces the system structure and work principle of the upgraded real time information system in Wangting Power Plant, and then expounds the realization way and function features of this system on B/S computing mode. The results of field application show the new system has good capability, reliability and expandability.
