Structural evolutions and electronic properties of Au_nGd(n=6–15) small clusters: A first principles study

Structural, electronic, and magnetic properties of Au_nGd(n = 6–15) small clusters are investigated by using first principles spin polarized calculations and combining with the ab-initio evolutionary structure simulations. The calculated binding energies indicate that after doping a Gd atom Aun Gd cluster is obviously more stable than a pure Au_(n+1) cluster.Au_6Gd with the quasiplanar structure has a largest magnetic moment of 7.421 μ_B. The Gd-4 f electrons play an important role in determining the high magnetic moments of Au_nGd clusters, but in Au_6Gd and Au_(12) Gd clusters the unignorable spin polarized effects from the Au-6 s and Au-5 d electrons further enhance their magnetism. The HOMO–LUMO(here, HOMO and LUMO stand for the highest occupied molecular orbital, and the lowest unoccupied molecular orbital, respectively)energy gaps of Au_nGd clusters are smaller than those of pure Au_(n+1) clusters, indicating that Au_nGd clusters have potential as new catalysts with enhanced reactivity.     

基于条元法的异步轧制金属三维塑性变形分析

采用条元法分析了异步轧制条件下金属在变形区内的变形情况,建立了适用于异步轧制的轧制压力公式及中性点坐标公式,并在计算摩擦力时考虑了粘着区的存在。通过仿真分析,得到了异步轧制条件下变形区内摩擦力的分布规律及应力、应变的分布规律,最后分析了不同速比对等效应力的影响以及不同入口厚度对轧制压力的影响。     

神经电生理记录的原理与方法

神经电生理记录技术是人们研究神经功能的重要手段,分为细胞内记录、细胞外记录、膜片钳记录和脑电图记录等。这些记录方法各有特点,在神经科学的研究中发挥着越来越重要的作用。