[理工] 材料動力學
有沒有學過材料動力學的高手可以幫忙解題！
想了很久還是解不出來啊，萬分感謝！
A steel bar, 25 cm long and 1 cm in diameter contains carbon
in the amount of 0.15 wt%.
A thin layer of carbon, 10^-4 moles/cm^2, is deposited upon one
end of the bar which is then annealed at a temperature of 1200K.
(1) How long will it take for the composition of the bar to
reach 0.25 wt% at a depth of 150 *10^-6m from the carbon coated end,
the first time? (10 wt%)
(2) Derive an expression for the velocity of the concentration front = 0.25%.
Comment on the direction of motion of this front at short time and long time.
( 5 wt %)
(3) How long will it take for the composition of the bar to drop back down
to 0.25 % carbon at a depth of 150*10^-6m from the carbon coated end?
再次感謝大大Q_Q
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