Back stress exerted by obstacle on leading dislocation. (It is supposed to be a short-range-force.) nrbdx =tpbdx dx virtual displacement

5.16 Dislocation in FCC crystals Perfect dislocation b =na, +nb. +nC

5. 8 The Stress Around a Dislocation 1. Screw dislocation: Displacement:

1. There have no two-phases area in diffusion area, every layer is single-phases 2. Phase's interface moves according to parabola law 3. Phase's width

36. 5 concentration dependence of D. Matano method d -C- dependence ll Matano method

1. Classification y Ideal or perfect crystal real or defect crystal According to dimension o point defect: vacancies, interstitial atoms s line defect dislocation planar defect: stacking fault o volume defect mosaic structure

1. The cause of rotation: Due to constraints, or boundary conditions imposed on the crystal. ll. The rule of rotation:

I Introduction Silicates are compounds that mainly composed of [sio4]. It is the essential components of most rock and soil, such as quartz, feldspar, mica etc

1. The structure of am b differs from those of either a or B 2. Its composition is variable to more or lessextension 3. Mixed bonding 4. Intermediate properties

第6章钢结构的正常使用极限状态 第7章钢结构的连接和节点构造(1)