磁头部的屏蔽以及阴极射线管内部磁屏蔽等电子部件的磁屏蔽都是不可缺少的 ,这样的部件屏蔽材料都是比较小的 ,磁特性和屏蔽性能都容易掌握。但是象磁屏蔽屋和电气室之类环境磁场屏蔽方面所使用的材料 ,其尺寸就要求很大 ,对其磁特性的测定和屏蔽性能的评价都是相当困难的。作 Shielding of the magnetic head and magnetic shielding of electronic components such as a magnetic shield inside the cathode ray tube are indispensable. Such shielding materials for the components are comparatively small, and magnetic characteristics and shielding properties are easy to grasp. However, the materials used in environmental magnetic field shielding such as magnetic shielded housing and electrical room are very large in size, and it is quite difficult to measure the magnetic properties and evaluate the shielding performance. Make