B, e-^^'a,^! 



A,e"^^ai^i 



B„e-''^'ao^y 



D,e""^'/^i^i 



C^e'^'P^^^ 



-(3) 



dl 



Cn + ie"^^/3„+,-n.. 



^n + 1 



Figure 23. Multilayer solid model. 



70 



