文章以锡盟—泰州特高压弱送端交流系统为背景,提出优化低压限流控制环节(voltage dependent current order limiter,VDCOL),以提高系统的稳定性。首先分析传统VDCOL的工作原理及局限性,提出以送端短路比与受端换流母线电压作为VDCOL截...文章以锡盟—泰州特高压弱送端交流系统为背景,提出优化低压限流控制环节(voltage dependent current order limiter,VDCOL),以提高系统的稳定性。首先分析传统VDCOL的工作原理及局限性,提出以送端短路比与受端换流母线电压作为VDCOL截止电压的变量,进而达到优化VDCOL的作用。使其截止电压为随逆变侧换流母线电压变化而变化的数值,可以兼顾交流与直流系统的恢复速度。其次,详细分析构建考虑直流系统动态特性的暂态能量函数的过程,并采用实时数字仿真仪(real time digital simulator,RTDS)搭建单机无穷大-直流的仿真算例。最后,基于时域仿真及暂态能量函数裕度方法,验证优化直流控制系统中的低压限流控制环节对送端交流系统稳定性的改善作用。展开更多
A special method is proposed of a laser-induced cavity pressure acceleration scheme for collimating,accelerating and guiding protons,using a single-cone target with a beam collimator through a target normal sheath acc...A special method is proposed of a laser-induced cavity pressure acceleration scheme for collimating,accelerating and guiding protons,using a single-cone target with a beam collimator through a target normal sheath acceleration mechanism.In addition,the problems involved are studied by using two-dimensional particle-in-cell simulations.The results show that the proton beam can be collimated,accelerated and guided effectively through this type of target.Theoretically,a formula is derived for the combined electric field of accelerating protons.Compared with a proton beam without a beam collimator,the proton beam density and cut-off energy of protons in the type II are increased by 3.3 times and 10%respectively.Detailed analysis shows that the enhancement is mainly due to the compact and strong sheath electrostatic field,and that the beam collimator plays a role in focusing energy.In addition,the simulation results show that the divergence angle of the proton beam in type II is less than 1.67 times that of type I.The more prominent point is that the proton number of type II is 2.2 times higher than that of type I.This kind of target has important applications in many fields,such as fast ion ignition in inertial fusion,high energy physics and proton therapy.展开更多
This study examines a Kuroshio main path(KMP) cut-off event east of Taiwan Island occurred in fall-winter2013–2014 and its impacts on the South China Sea(SCS) by analyzing satellite altimetry and mooring observations...This study examines a Kuroshio main path(KMP) cut-off event east of Taiwan Island occurred in fall-winter2013–2014 and its impacts on the South China Sea(SCS) by analyzing satellite altimetry and mooring observations. Satellite altimeter sea level anomaly(SLA) images reveal a complete process that a huge cyclonic eddy(CE) from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014. Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82% from 17×106 m^3/s in September to 3×106 m^3/s in November 2013. The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait. Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event.展开更多
Ternary and quadruple lithium silicon nitride anode materials for lithium ion batteries with different precursors were prepared by the simple process of high-energy ball milling. High capacity and excellent cyclabilit...Ternary and quadruple lithium silicon nitride anode materials for lithium ion batteries with different precursors were prepared by the simple process of high-energy ball milling. High capacity and excellent cyclability were obtained. The influence of precursor introduction on the electrochemical performance of products was investigated. This research reveals that the electrochemical performance of lithium silicon hitilde can be enhanced significantly by doping O. The cyclability of quadruple lithium silicon nitfide can be optimized remarkably by controlling the introduction quantity of the precursors. It is possible for the composite to be used as a capacity compensator within a wide voltage cut-off window.展开更多
文摘文章以锡盟—泰州特高压弱送端交流系统为背景,提出优化低压限流控制环节(voltage dependent current order limiter,VDCOL),以提高系统的稳定性。首先分析传统VDCOL的工作原理及局限性,提出以送端短路比与受端换流母线电压作为VDCOL截止电压的变量,进而达到优化VDCOL的作用。使其截止电压为随逆变侧换流母线电压变化而变化的数值,可以兼顾交流与直流系统的恢复速度。其次,详细分析构建考虑直流系统动态特性的暂态能量函数的过程,并采用实时数字仿真仪(real time digital simulator,RTDS)搭建单机无穷大-直流的仿真算例。最后,基于时域仿真及暂态能量函数裕度方法,验证优化直流控制系统中的低压限流控制环节对送端交流系统稳定性的改善作用。
文摘A special method is proposed of a laser-induced cavity pressure acceleration scheme for collimating,accelerating and guiding protons,using a single-cone target with a beam collimator through a target normal sheath acceleration mechanism.In addition,the problems involved are studied by using two-dimensional particle-in-cell simulations.The results show that the proton beam can be collimated,accelerated and guided effectively through this type of target.Theoretically,a formula is derived for the combined electric field of accelerating protons.Compared with a proton beam without a beam collimator,the proton beam density and cut-off energy of protons in the type II are increased by 3.3 times and 10%respectively.Detailed analysis shows that the enhancement is mainly due to the compact and strong sheath electrostatic field,and that the beam collimator plays a role in focusing energy.In addition,the simulation results show that the divergence angle of the proton beam in type II is less than 1.67 times that of type I.The more prominent point is that the proton number of type II is 2.2 times higher than that of type I.This kind of target has important applications in many fields,such as fast ion ignition in inertial fusion,high energy physics and proton therapy.
基金The National Natural Science Foundation of China under contract No.41776034the Ministry of Science and Technology of Taiwan under contract Nos MOST 105-2611-M-019-001 and MOST 106-2611-M-019-015+1 种基金the GASI Project under contract Nos GASI-IPOVAI-01-02 and GASI-02-SCS-YGST2-02the Foundation of Guangdong Province for Outstanding Young Teachers in University under contract No.YQ201588
文摘This study examines a Kuroshio main path(KMP) cut-off event east of Taiwan Island occurred in fall-winter2013–2014 and its impacts on the South China Sea(SCS) by analyzing satellite altimetry and mooring observations. Satellite altimeter sea level anomaly(SLA) images reveal a complete process that a huge cyclonic eddy(CE) from the Pacific collided with the Kuroshio and the western boundary from 15 October 2013 to 15 January 2014. Mooring observations evidenced that the Kuroshio upper ocean volume transport was cut off more than 82% from 17×106 m^3/s in September to 3×106 m^3/s in November 2013. The KMP cut-off event caused the Kuroshio branching and intruding into the SCS and strengthened the eddy kinetic energy in the northern SCS west of the Luzon Strait. Using the total momentum as a dynamic criterion to determine the role of eddy collision with the Kuroshio reasonably explains the KMP cut-off event.
基金This study is f'mancially supported by the National Natural Science Foundation of China (No.50502009)the Natural Science Foundation of Liaoning Province of China (No.20072146).
文摘Ternary and quadruple lithium silicon nitride anode materials for lithium ion batteries with different precursors were prepared by the simple process of high-energy ball milling. High capacity and excellent cyclability were obtained. The influence of precursor introduction on the electrochemical performance of products was investigated. This research reveals that the electrochemical performance of lithium silicon hitilde can be enhanced significantly by doping O. The cyclability of quadruple lithium silicon nitfide can be optimized remarkably by controlling the introduction quantity of the precursors. It is possible for the composite to be used as a capacity compensator within a wide voltage cut-off window.
