Topological superconductors carry globally protected gapless boundary excitations, which are robust under local perturbations, and thus exhibit both fundamental and applicational importance. An unconventional pairing ...Topological superconductors carry globally protected gapless boundary excitations, which are robust under local perturbations, and thus exhibit both fundamental and applicational importance. An unconventional pairing with p-wave symmetry, such as a nontrivial topology in the superconductor’s wavefunction, is required to generate a non-zero Berry phase. Until now, the Bi2 Te3/2 H–NbSe2 heterostructure has proven to be a practical way to realize a topological superconductor in real materials. This complex system, where odd numbers of spin-momentum locked Dirac cone surface states on the topological insulator Bi2 Te3 become superconducting, induced by the proximate effect from the underlying s-wave superconductor 2 H–NbSe2, realizes an effective two-dimensional(2 D) spinless px + i py topological superconductor. In this review article, we summarize the recent experimental progress of the successful synthesis of Bi2 Te3/2 H–NbSe2 heterostructures using molecular beam epitaxy, determining the thickness limit of the heterostructure, detecting the long thought Majorana quasiparticle inside a magnetic vortex core state by means of scanning tunneling microscopy and demonstration of the unique spatial and spin properties of a Majorana zero mode.展开更多
In a superconducting topological insulator, a superconducting vortex line can trap a one-dimensional topological band with localized Majorana zero modes at the ends. Here, we study the effect of hexagonal warping and ...In a superconducting topological insulator, a superconducting vortex line can trap a one-dimensional topological band with localized Majorana zero modes at the ends. Here, we study the effect of hexagonal warping and its corresponding symmetry-breaking effect on vortex phase transition. We perform both analytical calculations based on a semiclassical formula and numerical calculations based on full quantum mechanics using the Bogoliubov-de Gennes equation. We find that the hexagonal warping term extends the topological region of the vortex line as the chemical potential changes and leads to MZMs, even in the absence of topological surface states.展开更多
文中针对某500 k V变电站发现的低零值绝缘子缺陷进行了红外热相技术检测劣化绝缘子的适用范围研究,分析了各个电压等级的盘形绝缘子串中电压分布规律,对劣化绝缘子在不同阻值、不同位置下的发热情况进行了计算,给出测试盲区的范围和改...文中针对某500 k V变电站发现的低零值绝缘子缺陷进行了红外热相技术检测劣化绝缘子的适用范围研究,分析了各个电压等级的盘形绝缘子串中电压分布规律,对劣化绝缘子在不同阻值、不同位置下的发热情况进行了计算,给出测试盲区的范围和改善方法。现场测试表明,该方法使红外热像技术在适用范围内检出劣化绝缘子的概率明显提高。展开更多
为实现输电线路瓷质绝缘子巡检的标准化作业和信息化管理,提高零值绝缘子在线检测准确率、安全性和易操作性,设计并开发了一套互联网地理信息系统WebGIS(Web geographic information system)红外热像零值绝缘子在线检测系统。基于J2EE...为实现输电线路瓷质绝缘子巡检的标准化作业和信息化管理,提高零值绝缘子在线检测准确率、安全性和易操作性,设计并开发了一套互联网地理信息系统WebGIS(Web geographic information system)红外热像零值绝缘子在线检测系统。基于J2EE实现的瘦客户端模式的WebGIS架构设计,以绝缘子串区域温度分布方差、温度最大差值,盘面之间平均温度最大差值,盘面与背景平均温度最大差值作为零值特征参数,并结合环境相对湿度,等值附盐密度共6个量作为BP神经网络输入,通过WebGIS技术和BP神经网络算法实现零值绝缘子地图定位和智能识别。经过110 kV线路实测验证,表明系统检测效果良好,适用于输电线路瓷质绝缘子的在线检测与管理。展开更多
零值绝缘子威胁输电线路安全稳定运行。通过光纤电场检测方式可以获得绝缘子串局部电场分布,从而识别零值片。设计了一款光纤电场检测履带机器人,并为分析其在检测过程中可能产生的误差和影响,提出识别判据,建立了220 k V绝缘子串真型...零值绝缘子威胁输电线路安全稳定运行。通过光纤电场检测方式可以获得绝缘子串局部电场分布,从而识别零值片。设计了一款光纤电场检测履带机器人,并为分析其在检测过程中可能产生的误差和影响,提出识别判据,建立了220 k V绝缘子串真型模型以及检测机器人等效模型,仿真分析了机器人构架在绝缘子串不同位置时的电场分布特性,并且研究了机器人材质、位置、尺寸等因素对局部电场畸变特征的影响,尤其是零值和非零值情况下的局部电场变化规律。研究结果揭示了光纤电场检测机器人对零值绝缘子局部电场畸变的影响,可为输配电外绝缘智慧运维提供技术支撑。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11674226,11790313,11521404,11634009,U1632102,11504230,11674222,11574202,11674226,11574201,U1632272,U1732273,U1732159,11655002,1674220,and 11447601)the National Key Research and Development Program of China(Grant Nos.2016YFA0300403,2016YFA0301003,2016YFA0300500,and 2016YFA0300501)+2 种基金the Fund from the Technology Commission of Shanghai Municipality(Grant Nos.15JC402300 and 16DZ2260200)the Key Research Program of the Chinese Academy of Sciences(Grant No.XDPB08-2)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB28000000)
文摘Topological superconductors carry globally protected gapless boundary excitations, which are robust under local perturbations, and thus exhibit both fundamental and applicational importance. An unconventional pairing with p-wave symmetry, such as a nontrivial topology in the superconductor’s wavefunction, is required to generate a non-zero Berry phase. Until now, the Bi2 Te3/2 H–NbSe2 heterostructure has proven to be a practical way to realize a topological superconductor in real materials. This complex system, where odd numbers of spin-momentum locked Dirac cone surface states on the topological insulator Bi2 Te3 become superconducting, induced by the proximate effect from the underlying s-wave superconductor 2 H–NbSe2, realizes an effective two-dimensional(2 D) spinless px + i py topological superconductor. In this review article, we summarize the recent experimental progress of the successful synthesis of Bi2 Te3/2 H–NbSe2 heterostructures using molecular beam epitaxy, determining the thickness limit of the heterostructure, detecting the long thought Majorana quasiparticle inside a magnetic vortex core state by means of scanning tunneling microscopy and demonstration of the unique spatial and spin properties of a Majorana zero mode.
基金supported by the Air Force Office of Scientific Research(AFOSR)(Grant No.FA9550-14-1-0168)supported by the National Natural Science Foundation of China(Grant No.11674278)+1 种基金the National Basic Research Program of China(Grant No.2014CB921203)the CAS Center for Excellence in Topological Quantum Computation,and the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDB28000000)
文摘In a superconducting topological insulator, a superconducting vortex line can trap a one-dimensional topological band with localized Majorana zero modes at the ends. Here, we study the effect of hexagonal warping and its corresponding symmetry-breaking effect on vortex phase transition. We perform both analytical calculations based on a semiclassical formula and numerical calculations based on full quantum mechanics using the Bogoliubov-de Gennes equation. We find that the hexagonal warping term extends the topological region of the vortex line as the chemical potential changes and leads to MZMs, even in the absence of topological surface states.
文摘文中针对某500 k V变电站发现的低零值绝缘子缺陷进行了红外热相技术检测劣化绝缘子的适用范围研究,分析了各个电压等级的盘形绝缘子串中电压分布规律,对劣化绝缘子在不同阻值、不同位置下的发热情况进行了计算,给出测试盲区的范围和改善方法。现场测试表明,该方法使红外热像技术在适用范围内检出劣化绝缘子的概率明显提高。
文摘为实现输电线路瓷质绝缘子巡检的标准化作业和信息化管理,提高零值绝缘子在线检测准确率、安全性和易操作性,设计并开发了一套互联网地理信息系统WebGIS(Web geographic information system)红外热像零值绝缘子在线检测系统。基于J2EE实现的瘦客户端模式的WebGIS架构设计,以绝缘子串区域温度分布方差、温度最大差值,盘面之间平均温度最大差值,盘面与背景平均温度最大差值作为零值特征参数,并结合环境相对湿度,等值附盐密度共6个量作为BP神经网络输入,通过WebGIS技术和BP神经网络算法实现零值绝缘子地图定位和智能识别。经过110 kV线路实测验证,表明系统检测效果良好,适用于输电线路瓷质绝缘子的在线检测与管理。
文摘零值绝缘子威胁输电线路安全稳定运行。通过光纤电场检测方式可以获得绝缘子串局部电场分布,从而识别零值片。设计了一款光纤电场检测履带机器人,并为分析其在检测过程中可能产生的误差和影响,提出识别判据,建立了220 k V绝缘子串真型模型以及检测机器人等效模型,仿真分析了机器人构架在绝缘子串不同位置时的电场分布特性,并且研究了机器人材质、位置、尺寸等因素对局部电场畸变特征的影响,尤其是零值和非零值情况下的局部电场变化规律。研究结果揭示了光纤电场检测机器人对零值绝缘子局部电场畸变的影响,可为输配电外绝缘智慧运维提供技术支撑。
