課程名稱︰材料科學導論
課程性質︰選
課程教師︰呂宗昕
開課學院：化工
開課系所︰工
考試日期（年月日）︰2011 6 21
考試時限（分鐘）：2hr
是否需發放獎勵金：yes
（如未明確表示，則不予發放）
試題 :
1.please state the physical meaning of the following terms:
(a)fatigue
(b)stress raiser
(c)creep
(d)Frenkel defect
(e)Fermi level
2.(a)a polystyrene component must not fail when a tensile stress of 1.5 MPa is
applied. determine the max. allowable surface crack length if the surface
energy of polystyrene is 0.7 J/m^2. assume a modulus of elasticity of 2.5GPa
(b)some aircraft component is fabricate ed from an aluminum alloy that has a
plane strain fracture toughness of 40MPa√m. It has been determined that
fracture results at a stress of 270MPa when the max. internal crack length
is 3mm. for the same component and alloy, will fracture occur at a stress
level of 310MPa when the maximum internal crack length is 2.2 mm? please
calculate the question and explain the reason
3.(a)calculate the minimum cation-to -anion radius ratio for a coordination
number of 4.
(b) draw the crystal structure for NaCl and BaTiO3.
4.(a)calculate the e and hole concentrations at 50度C. the eletrical
conductivity at 50度C is 10.5e-4 (sigma-m)^-1 , and the electron and hole
mobilities are 0.18 and 0.064(m^2/V-s e=1.6e-19
(b) when 3e15 m^-3 phosphorus is doped in silicon, calculate the coductivity
at 50度C
5.a parallel-plane capacitor has an area of 9e-4 m^2 and a plate-separation of
5e-4m. the applied voltage is 20V. the polarization of the inserted material
is 6e-7C/m^2. calculate the dielectric constant of the material, the
capacitance of the capacitor, the stored charge on each plate, and the
dielctric displacement.
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