共查询到19条相似文献,搜索用时 62 毫秒
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本利用动态激光散斑测振技术测量超小型物体振动特性的实验系统,研究了123YB-CO温超导体的动态力学性能,运用谱分析仪和时间域分析方法了动态响应信号,识别出了超导体梁的前五阶频率和模态,并根据基频计算了材料的动态模量,为小尺寸脆性功能材料的力学性能测试提供了一种有效的实验方法。 相似文献
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基于电磁学和超导物理学的原理和相关实验数据,说明所谓的室温常压超导体LK-99在圆盘状钕铁硼永磁体极面的半悬浮应来源于其中的铁磁杂质碎片所受的转矩和引力。涂覆Y-Ba-Cu-O的高温超导体薄片在这种永磁体磁极上下的锁定悬浮,则起因于不均匀外磁场中超导体位置变化感生的超导电流所受该磁场的位置回复洛伦兹力,而并非迈斯纳效应和所谓的量子锁定的结果。 相似文献
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Lateral magnetic stiffness under different parameters in a high-temperature superconductor levitation system 下载免费PDF全文
《中国物理 B》2021,30(7):77404-077404
Magnetic stiffness determines the stability of a high-temperature superconductor(HTS) magnetic levitation system.The quantitative properties of the physical and geometrical parameters that affect the stiffness of HTS levitation systems should be identified for improving the stiffness by some effective methods. The magnetic stiffness is directly related to the first-order derivative of the magnetic force with respect to the corresponding displacement, which indicates that the effects of the parameters on the stiffness should be different from the relationships between the forces and the same parameters.In this paper, we study the influences of some physical and geometrical parameters, including the strength of the external magnetic field(B0) produced by a rectangular permanent magnet(PM), critical current density(Jc), the PM-to-HTS area ratio(α), and thickness ratio(β), on the lateral stiffness by using a numerical approach under zero-field cooling(ZFC)and field cooling(FC) conditions. In the first and second passes of the PM, the lateral stiffness at most of lateral positions essentially increases with B0 increasing and decreases with β increasing in ZFC and FC. The largest lateral stiffness at every lateral position is almost produced by the minimum value of Jc, which is obviously different from the lateral force–Jc relation. The α-dependent lateral stiffness changes with some parameters, which include the cooling conditions of the bulk HTS, lateral displacement, and movement history of the PM. These findings can provide some suggestions for improving the lateral stiffness of the HTS levitation system. 相似文献
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Angular dependence of vertical force and torque when magnetic dipole moves vertically above flat high-temperature superconductor 下载免费PDF全文
The interaction between a permanent magnet (PM) assumed as a magnetic dipole and a flat high-temperature superconductor (HTS) is calculated by the advanced frozen-image model. When the dipole vertically moves above the semi-infinite HTS, the general analytical expression of vertical force and that of torque are obtained for an arbitrary angle between the magnetization direction of the PM and the c axis of the HTS. The variations of the force and torque are analyzed for angle and vertical movements in both zero-field cooling (ZFC) condition and field cooling (FC) condition. It is found that the maximum vertical repulsive or attractive force has the positive or negative cosine relation with the angle. However, the maximum torque has the positive or negative sine relation. From the viewpoint of the rotational equilibrium, the orientation of the magnetic dipole with zero angle is deemed to be an unstable equilibrium point in ZFC, but the same orientation is considered as a stable equilibrium point in FC. In addition, both of the variation cycles of the maximum force and torque with the angle are π. 相似文献
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铁基超导体具有极高的上临界磁场、较小的各向异性、简单的制备工艺等优点,在高场超导磁体、核磁共振谱仪、可控核聚变装置、高能粒子加速器等领域具有重要的应用前景。为满足上述高场强电应用需求,必须制备出高性能超导线带材。文章详细介绍了多种体系铁基超导线带材的研究进展,分析当前线带材研究中存在的问题,提出改善线材传输性能的途径,并对铁基超导线材的发展趋势进行展望。 相似文献
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在多晶系统的MgB2超导体中存在晶粒间较小的整体电流和晶粒内大的局域电流.用改变升温速率的方法制备了不同晶粒大小和晶粒连接性的MgB2样品,并对它们的晶粒大小进行了统计.采用一种测量超导临界电流密度的Campbell法,分别测量和计算得到了它们的整体电流和局域电流密度.研究表明:长时间的烧结造成晶粒变大,材料有较大的整体临界电流密度,而短时间烧结的样品则相反;同时发现晶粒细化只提高了样品的局域临界电流密度,而且样品内部缺陷、杂质及晶界等因素是影响MgB2超导体整体电流传输的主要因素. 相似文献
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LabVIEW软件在模拟电路实验中的应用 总被引:2,自引:0,他引:2
虚拟仪器是现代实验的重要组成部分.通过采用虚拟仪器开发语言LabVIEW开发一个积分微分器,阐述基于LabVIEW的虚拟仪器在模拟电路实验中应用的实用性. 相似文献
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Zeeman effects on Josephson current in d-wave superconductor/d-wave superconductor junctions 下载免费PDF全文
This paper solves a self-consistent equation for the d-wave
superconducting gap and the effective exchange field in the
mean-field approximation, and studies the Zeeman effects on the
d-wave superconducting gap and thermodynamic potential. The Josephson
currents in the d-wave superconductor(S)/insulating layer(I)/d-wave S
junctions are calculated as a function of the temperature, exchange
field, and insulating barrier strength under a Zeeman magnetic field
on the two d-wave Ss. It is found that the Josephson critical
currents in d-wave S/d-wave S junction to a great extent depend on
the relative orientation of the effective exchange field of the two S
electrodes, and the crystal orientation of the d-wave S. The exchange
field under certain conditions can enhance the Josephson critical
current in a d-wave S/I/d-wave S junction. 相似文献
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从Ginzburg-Landau理论出发,对理想第二类超导体的下临界磁场做计算。通过比较两相的吉布斯自由能,特别是考虑相变时的熵增,最终求得下临界场的新公式,得到纯超导体的下临界场对温度的依赖与经验公式有所不同。作者把这种不同归结为超导体的G-L参数对温度的依赖。 相似文献