| 摘要 |
PROBLEM TO BE SOLVED: To provide a method capable of detecting a crack generated inside a furnace wall or the like, accurately by a simple method.SOLUTION: A distance spectrum and a phase spectrum are measured by performing transmission/reception of a microwave or a millimeter wave to/from a detection object before use and after use of a prescribed time on the same condition, and each distance spectrum or each phase spectrum is compared between each condition before use and after use of the prescribed time. It is determined that a crack is generated after use of the prescribed time when a difference is confirmed therebetween. |
