叠堆相邻部件之间的接触区域（例如换能器—增幅杆接头、增幅杆—变幅杆接头、后驱动块—陶瓷接头等）。
The area of contact between adjacent components of a stack (e.g., transducer-booster joint, booster-horn joint, back driver-ceramic joint, etc.).