The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges be...The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges between 0.2 and 0.4.This enhancement prompts a critical question:to what extent can quantum wells(QWs)be strained while still preserving the fundamental QSHI phase?In this study,we demonstrate the controlled molecular beam epitaxial growth of highly strained-layer QWs with an indium composition of x=0.5.These structures possess a substantial compressive strain within the In_(0.5)Ga_(0.5)Sb QW.Detailed crystal structure analyses confirm the exceptional quality of the resulting epitaxial films,indicating coherent lattice structures and the absence of visible dislocations.Transport measurements further reveal that the QSHI phase in InAs/In_(0.5)Ga_(0.5)Sb QWs is robust and protected by time-reversal symmetry.Notably,the edge states in these systems exhibit giant magnetoresistance when subjected to a modest perpendicular magnetic field.This behavior is in agreement with the𝑍2 topological property predicted by the Bernevig–Hughes–Zhang model,confirming the preservation of topologically protected edge transport in the presence of enhanced bulk strain.展开更多
针对电力电子化配电网谐波源随机波动引发的治理效率与成本问题,提出融合谐波源随机表征与多目标粒子群-遗传算法(multi-objective particle swarm optimization-genetic algorithm,MOPSO-GA)的并联有源电力滤波器(shunt active power f...针对电力电子化配电网谐波源随机波动引发的治理效率与成本问题,提出融合谐波源随机表征与多目标粒子群-遗传算法(multi-objective particle swarm optimization-genetic algorithm,MOPSO-GA)的并联有源电力滤波器(shunt active power filter,SAPF)优化配置策略。基于中心极限定理,采用正态分布与均匀分布构建谐波幅值与相位的概率模型,结合MOPSO-GA算法实现多目标优化。仿真结果表明,在IEEE 18节点系统中仅配置3台SAPF即可将总谐波畸变率从19.88%降至3.32%,电压偏差从10.4%控制至4.5%,SAPF较传统MOPSO算法减少1台,总容量更经济,算法收敛速度与帕累托前沿分布性显著提升。并进一步通过RT-Lab半实物实验平台验证,在真实谐波源下将关键节点谐波电压畸变率从25.24%降至2.12%,该策略为复杂配电网谐波治理提供高效经济的解决方案。展开更多
基金supported by the Strategic Priority Research Program of Chinese Academy of Sciences (Grant Nos.XDB28000000 and XDB0460000)the Quantum Science and Technology-National Science and Technology Major Project (Grant No.2021ZD0302600)the National Key Research and Development Program of China(Grant No.2024YFA1409002)。
文摘The hybridization gap in strained-layer InAs/In_(x)Ga_(1−x) Sb quantum spin Hall insulators(QSHIs)is significantly enhanced compared to binary InAs/GaSb QSHI structures,where the typical indium composition,x,ranges between 0.2 and 0.4.This enhancement prompts a critical question:to what extent can quantum wells(QWs)be strained while still preserving the fundamental QSHI phase?In this study,we demonstrate the controlled molecular beam epitaxial growth of highly strained-layer QWs with an indium composition of x=0.5.These structures possess a substantial compressive strain within the In_(0.5)Ga_(0.5)Sb QW.Detailed crystal structure analyses confirm the exceptional quality of the resulting epitaxial films,indicating coherent lattice structures and the absence of visible dislocations.Transport measurements further reveal that the QSHI phase in InAs/In_(0.5)Ga_(0.5)Sb QWs is robust and protected by time-reversal symmetry.Notably,the edge states in these systems exhibit giant magnetoresistance when subjected to a modest perpendicular magnetic field.This behavior is in agreement with the𝑍2 topological property predicted by the Bernevig–Hughes–Zhang model,confirming the preservation of topologically protected edge transport in the presence of enhanced bulk strain.
文摘针对电力电子化配电网谐波源随机波动引发的治理效率与成本问题,提出融合谐波源随机表征与多目标粒子群-遗传算法(multi-objective particle swarm optimization-genetic algorithm,MOPSO-GA)的并联有源电力滤波器(shunt active power filter,SAPF)优化配置策略。基于中心极限定理,采用正态分布与均匀分布构建谐波幅值与相位的概率模型,结合MOPSO-GA算法实现多目标优化。仿真结果表明,在IEEE 18节点系统中仅配置3台SAPF即可将总谐波畸变率从19.88%降至3.32%,电压偏差从10.4%控制至4.5%,SAPF较传统MOPSO算法减少1台,总容量更经济,算法收敛速度与帕累托前沿分布性显著提升。并进一步通过RT-Lab半实物实验平台验证,在真实谐波源下将关键节点谐波电压畸变率从25.24%降至2.12%,该策略为复杂配电网谐波治理提供高效经济的解决方案。
