L. Zhou
,
X.Q. Wei
,
N.G. Zhou
金属学报(英文版)
Molecular dynamics simulations of high temperature annealing of copper bicrystals
have been carried out. The bicrystals have planar grain boundaries, and the gain
size varies in nano range. An EAM(Embedded Atom Method) potential of FS type is
used for calculating the interatomic forces. The results show that in nanocrystalline
copper, GB migration driven by inter-GB reaction can take place. A critical grain
size is identi¯ed, below which the inter-GB reaction becomes strong enough to trigger
GB motion, which accelerates rapidly and leads to annihilation of the grain bound-
aries. The critical size is found to be 16 atomic radii. A \through intermediate grain
mechanism" is identi¯ed for the nano-grain boundary motion observed, which is never
reported for GB migrations of conventional polycrystalline metals.
关键词:
grain boundary migration
,
null
,
null
高健
,
康健
,
吴学玲
,
徐競
,
李邦梅
,
邱冠周
中国有色金属学报
以分离于江西某铜矿的嗜铁钩端螺旋菌(L. ferriphilum YSK)菌株为研究对象,报道不同Fe2+浓度对 L. ferriphilum生长活性的影响.结果表明,YSK菌株生长最适宜的Fe2+浓度约为0.1 mol/L.当初始Fe2+浓度为0.4 mol/L时,进入对数生长期前很明显需要一个较长的延迟期,表明该Fe2+浓度对细胞的生长产生较强的抑制作用;当初始Fe2+浓度为0.6 mol/L时,YSK菌株的生长完全受到抑制.尽管高浓度的Fe2+抑制细胞的生长,但受到抑制而不生长繁殖的YSK细胞仍然具有氧化Fe2+的能力.
关键词:
L.ferriphilum YSK菌株
,
Fe2+
,
生长活性