| 摘要 |
<p>The sandwich or composite plate (1) consists of a central layer (7) of polymer (8) and conducting metal balls (9) enclosed by external metallic facing plates (3,5). An electrical signal of frequency (f) is applied across the sandwich by electrodes (11,13) which are in contact with the external plates (3,5). The central layer (7) behaves as a parallel resistive and capacitative circuit and the voltage/current phase angle may be measured. This angle allows the fraction of metallic balls (9) to be calculated and provided this is above a preset threshold the external plates (3,5) may be satisfactorily welded together.</p> |
