Fundamental Studies on Characteristic Evaluation and Application of Bulk Superconductor

1.采用YBCO本体和多磁体设计并构建了一种新型的主动磁悬浮系统。采用三磁体和五磁体系统控制悬浮高度，验证了悬浮体的连续悬浮效果，并利用有限元程序研究了悬浮体内部的电磁特性。提出了一种二维运动的磁悬浮装置，即“悬浮X-Y传输体”。针对实际设计的悬浮X-Y运输体，对其升力和恢复力进行了实验研究，并基于三维混合FE-BE方法开发了仿真程序来分析其动态电磁行为。然后通过实验和数值模拟阐明了各种作用力与超电流和磁场分布之间的关系。并进行了浮式输送机的设计。我们制作并测试了一种具有双面一次和现场冷却YBCO散装二次的线性同步执行器。实验研究了同步转矩、启动推力和拉入特性等静态特性。并且我们开发了一个基于FEM的仿真程序来研究暴露在初级绕组产生的磁场下的体内电磁行为。实验研究了不同振幅和频率的外部交流磁场作用于圆盘状YBCO体时捕获场的跃迁。并利用新开发的基于有限元法的计算机程序进行了数值模拟。在50 Hz的长期应用场下进行了陷场衰减实验。衰减突然变大，最后被困场消失。这意味着随时间变化的磁场改变了体内的屏蔽电流分布，瞬态磁通运动导致温度升高，最终导致捕获场减小。少

1.A new type of active-maglev system is designed and constructed using YBCO bulk and multiple electromagnets. And the continuous levitation was demonstrated with controlling the levitation height using three and five electromagnets systems and electromagnetic behavior within the bulk was investigated using a FEM computer program.2.A magnetic levitating device was proposed with two-dimensional movement, namely a 'levitating X-Y transporter'. For a real design of levitating X-Y transporter, the lift and the restoring force were examined experimentally and a simulation program was newly developed based on the three-dimensional hybrid FE-BE method to analyze the dynamic electromagnetic behaviors of the HTS bulk. Then the relationship between the various forces and distributions of supercurrent and magnetic field was clarified through experiments and numerical simulation. And the design of a levitating transporter was also performed.3.We fabricated and tested a linear synchronous actuator w … More ith double-sided primary and field-cooled YBCO bulk secondary. We experimentally investigated the static characteristic in points of synchronous torque, the starting thrust and the pull-in characteristics. And we developed a simulation program based on FEM to investigate electromagnetic behavior within the bulk exposed to the magnetic field generated by the primary winding.4.The transition of trapped field was experimentally investigated while applying external AC magnetic field with various amplitude and frequency to a disk-shaped YBCO bulk. And the numerical simulation was also performed using a newly developed computer program based on the FEM. The experiment of trapped field attenuation was carried out in long term applying field with a frequency of 50 Hz. The attenuation is abruptly large and finally the trapped field is disappeared. This means that shielding current distribution within the bulk is changed by the time-varying magnetic field and the transient magnetic flux movement results in temperature rise and finally the reduction of the trapped field. Less