南京大学材料物理基础2003真题

一、一、填空(Fill in the blanks)(55分)

1.1.對於單種原子構成的金屬，fcc和bcc晶體的配位數分別為和。(4分)

With only one kind of metallic atom present, the coordination number for fcc and bcc metals are and , respectively.

2.2.對於單種原子構成的金屬，立方晶體的每個結晶學原胞中包含4個原子。(3分)

With only one kind of metallic atom present, there are four metal atoms per unit cell of a cubic metal.

3.3.晶體的多形性是指“同一成分具有多種結構”，這類晶體的典型例子如：和，

或和。(6分)

Polymorph means “multiple structure of the same composition”, examples include and , or and .

4.4.如果只有光子提供能量，在磷化鎵(GaP)中能引起光電導的光的波長最長可為 nm(GaP的

帶隙為2.3eV)，這種波長的光是否可見光？。(4分)

The largest wavelength of the light necessary to cause photoconduction in gallium phosphide(GaP) is nm, if all the energy comes from the photons. (The energy gap of

GaP is 2.3eV). Is this light visible or not?

5. 5.半導體的電導是由負載流子在帶的電導和正載流子在帶的電導之和。(4分)

The conductivity of a semiconductor is the sum of the conductivity in the band by

negative carriers and the conductivity in the band by positive carriers.

6. 6.鐵電材料或壓電材料中是否存在對稱中心？ (3分)

Is there any center of symmetry present in the ferroelectric or piezoelectric materials?

7.7.根據圖1的相圖，對於50kg的20Cu-80Ni合金，

a) 液相線溫度為℃。 b) 固相線溫度為℃。

c) 在1400℃，液相中最多可含有約％Ni。

d) 在1400℃a相中Cu的含量最大約為％

e) 在1400℃，20Cu-80Ni合金中的主要相為。

f) 在1400℃，液相和固相的比值為比。(14分)

According to Fig. 1, consider 50kg of a 20Cu-80Ni alloy,

a) The liquidus temperature is ℃.

b) The solidus temperature is ℃.

c) At 1400℃, the liquid can contain up to about %Ni.

d) The maximum copper in a at 1400℃ is about %.

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