Derive and sketch the electrical field E of doping concentrations And(x) are given by,

(a) Nd (x) = ax, where a is a constant;
(b) Nd (x) = Noe-ax ;
(c) Nd (x) = 1016 – 1019x (cm-1), where x is distance from the slab surface and end at x = L
(d) In part (c), calculate Emax at x = 0 and the thickness L of the semiconductor lab if Nd reduce to 50% of the surface value.

Ajournal bearing has a journal diameter of 3.250 in with a unilateral tolerance of 20.003 in. the bushing bore has a diameter of 3.256 in and a unilateral tolerance of 0.004 in. the bushing is 2.8 in long and supports a 700-lbf load. the journal speed is 900 rev/min. find the minimum oil film thickness and the maximum film pressure for both sae 20 and sae 20w-30 lubricants, for the tightest assembly if the operating film temperature is 160°f. a computer code is appropriate for solving this problem.