In a step-down chain a solitary wave (SW) evolves into an SW train (SWT),but the formation of well-defined SWT takes time and space and little is known of the process from immature into mature SWT.We therefore perform a detailed numerical study of this process by analysing the local velocity amplitude and peak overlap of immature ordered SWs.The first SW continuously increases to maximal velocity amplitude and peak overlap until it is matured,but for following SWs there exist a minimal and maximal value of local velocity amplitude and,a minimal and maximal value of local peak overlap,clarifying the details of the energy propagation along the stepped chain.The immature and mature SWTs show the same dependence of the phase velocity on the SWs sequence.These provide guidelines for when or where the attention should be paid in the study of SWT.
Molecular dynamics(MD) simulations were performed to investigate the glass forming ability(GFA) and microscopic structural properties of liquid Cu-Zr alloys.Based on the analysis of composition dependences of the reduced glass transition temperatures and the excess volume,we found that the Cu-Zr glasses have the largest GFA at Cu65Zr35 composition.To get more detailed information of local structure,we calculated the pair correlation functions,partial pair correlation functions,the excess entropy,chemical order parameter,coordination number,and Voronoi index of Cu-Zr liquids.We found that there exists an obvious and close relationship among the GFA,the excess entropy calculated using the total pair correlation functions,chemical order parameters,and some Cu centered cluster with Voronoi index <0,2,8,1> and Zr centered cluster with Voronoi index <0,3,6,4>,which all have nonlinear dependences on Cu/Zr concentration and have extreme values at liquid Cu65Zr35 composition.
