: , ( 15 ) ?
- ( ), , , , , ( ) . (.. , ), .
: rSm(t) , ?
:
t = 0 NPm = 0 NSm = NSm0 + NPm0 (t) =
( NSm0 NPm0 149Sm 149Pm).
rSm(t), Np .20.5.
rSm(t)
0 (³ 15 )
t
Np ³ 70% Np
rSmo
Np = 30% Np
rSm Np = 60% Np
. 20.5.
.
, , , : ( ) .
(>7080%) , , , , .