铋锑合金(Bi1-xSbx)的能带结构随x而变化,在拓扑绝缘体和拓扑半金属的研究中具有重要的地位。对Bi0.96Sb0.04的研究表明,该合金的电阻率随温度的升高先升后降,具有典型的半金属特点。在极低温度下可以观察到纵向磁电阻和横向霍尔电阻随...铋锑合金(Bi1-xSbx)的能带结构随x而变化,在拓扑绝缘体和拓扑半金属的研究中具有重要的地位。对Bi0.96Sb0.04的研究表明,该合金的电阻率随温度的升高先升后降,具有典型的半金属特点。在极低温度下可以观察到纵向磁电阻和横向霍尔电阻随外磁场的Shubnikov de Haas振荡,且两者的振荡相位正好相反。随磁场增加的不饱和线性磁电阻可以解释为在具有无能隙或极小能隙材料中,费米面附近电子线性色散关系带来的量子效应。在低温下,通过外加磁场可使简并的Dirac锥电子,分离成不同手性的Weyl电子,在磁场方向与电流方向一致时观察到了手性反常引起的负磁电阻效应。展开更多
The linear and non-linear math models of the switched reluctance generator (SRG) in generator mode were established in this work. The phase current and energy conversion process during generator operation were simulat...The linear and non-linear math models of the switched reluctance generator (SRG) in generator mode were established in this work. The phase current and energy conversion process during generator operation were simulated by the linear math model. The non-linear math model was used to analyze the characteristics of the SRG operation in self-excitation mode and in separately-excitation mode. Some important findings on how the SRG is operated and controlled were obtained in this study, which provides theoretical basis for further design and experimental study.展开更多
Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy we...Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology and structure of the multilayered nanowire arrays. Vibrating sample magnetometer and physical property measurement system were used to measure their magnetic and giant magnetoresistance （GMR） properties. The effect of sub-layer thickness on the magnetic and GMR properties was investigated. The results indicate that magnetic properties of electmdeposited nanowires are not affected obviously by Cu layer thickness, while magnetic layers （Ni-Fe and Co layers） have significant influence. In addition, GMR ratio presents an oscillatory behavior as Cu layer thickness changes. The magnetic and GMR properties of the multilayered nanowire arrays are optimum at room temperature for the material structure of Ni-Fe （25 nm）/Cu （15 nm）/Co （25 nm）/Cu （15 nm） with 30 deposition cycles.展开更多
文摘铋锑合金(Bi1-xSbx)的能带结构随x而变化,在拓扑绝缘体和拓扑半金属的研究中具有重要的地位。对Bi0.96Sb0.04的研究表明,该合金的电阻率随温度的升高先升后降,具有典型的半金属特点。在极低温度下可以观察到纵向磁电阻和横向霍尔电阻随外磁场的Shubnikov de Haas振荡,且两者的振荡相位正好相反。随磁场增加的不饱和线性磁电阻可以解释为在具有无能隙或极小能隙材料中,费米面附近电子线性色散关系带来的量子效应。在低温下,通过外加磁场可使简并的Dirac锥电子,分离成不同手性的Weyl电子,在磁场方向与电流方向一致时观察到了手性反常引起的负磁电阻效应。
文摘The linear and non-linear math models of the switched reluctance generator (SRG) in generator mode were established in this work. The phase current and energy conversion process during generator operation were simulated by the linear math model. The non-linear math model was used to analyze the characteristics of the SRG operation in self-excitation mode and in separately-excitation mode. Some important findings on how the SRG is operated and controlled were obtained in this study, which provides theoretical basis for further design and experimental study.
基金Supported by the Natural Science Foundation of Tianjin,China(08JCZDJC17400)
文摘Ni-Fe/Cu/Co/Cu multilayered nanowire arrays were electrodeposited into anodic aluminum oxide template by using dual-bath method at room temperature. Scanning electron microscopy and transmission electron microscopy were used to characterize the morphology and structure of the multilayered nanowire arrays. Vibrating sample magnetometer and physical property measurement system were used to measure their magnetic and giant magnetoresistance （GMR） properties. The effect of sub-layer thickness on the magnetic and GMR properties was investigated. The results indicate that magnetic properties of electmdeposited nanowires are not affected obviously by Cu layer thickness, while magnetic layers （Ni-Fe and Co layers） have significant influence. In addition, GMR ratio presents an oscillatory behavior as Cu layer thickness changes. The magnetic and GMR properties of the multilayered nanowire arrays are optimum at room temperature for the material structure of Ni-Fe （25 nm）/Cu （15 nm）/Co （25 nm）/Cu （15 nm） with 30 deposition cycles.
