This report is to seek the disk-type minimal surfaces spanning a given boundary in a Riemannian manifold N. While there have been many researches on stable minimal surfaces, it remains an interesting problem to look f...This report is to seek the disk-type minimal surfaces spanning a given boundary in a Riemannian manifold N. While there have been many researches on stable minimal surfaces, it remains an interesting problem to look for unstable minimal surfaces. Since the existence of unstable surface in R^3 was first proved by Morse-Tompkins and Shiffman in 1939, little progress has been made in this field except for some special cases.展开更多
大部分工矿企业的用电情况复杂,大量非线性负荷使供电系统中高次谐波含量增加,引起电网电压畸变,常规无功补偿设备无法有效应对。针对上述现象,本文提出了一种由三电平拓扑电路组成的有源电力滤波器(APF)模块设备,安装在变压器二次侧0.4...大部分工矿企业的用电情况复杂,大量非线性负荷使供电系统中高次谐波含量增加,引起电网电压畸变,常规无功补偿设备无法有效应对。针对上述现象,本文提出了一种由三电平拓扑电路组成的有源电力滤波器(APF)模块设备,安装在变压器二次侧0.4 k V母线上,对电源系统进行谐波治理和无功补偿。该模块运行速度快、功率损耗低、体积小、重量轻,较适宜于现场的安装改造。工程实践证明该模块能够有效解决供电系统谐波污染和无功补偿问题。展开更多
文摘This report is to seek the disk-type minimal surfaces spanning a given boundary in a Riemannian manifold N. While there have been many researches on stable minimal surfaces, it remains an interesting problem to look for unstable minimal surfaces. Since the existence of unstable surface in R^3 was first proved by Morse-Tompkins and Shiffman in 1939, little progress has been made in this field except for some special cases.
文摘大部分工矿企业的用电情况复杂,大量非线性负荷使供电系统中高次谐波含量增加,引起电网电压畸变,常规无功补偿设备无法有效应对。针对上述现象,本文提出了一种由三电平拓扑电路组成的有源电力滤波器(APF)模块设备,安装在变压器二次侧0.4 k V母线上,对电源系统进行谐波治理和无功补偿。该模块运行速度快、功率损耗低、体积小、重量轻,较适宜于现场的安装改造。工程实践证明该模块能够有效解决供电系统谐波污染和无功补偿问题。
