The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of interme...The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles.展开更多
利用2008~2019年A股880家上市公司数据,考虑异质机构投资者的因素的情况下,考察流动性与股价崩盘风险之间的作用关系。研究表明:1) 流动性与股价崩盘风险之间呈现明显的正向相关性,尤其在稳定型机构分组中表现更为显著;2) 机构投资者在...利用2008~2019年A股880家上市公司数据,考虑异质机构投资者的因素的情况下,考察流动性与股价崩盘风险之间的作用关系。研究表明:1) 流动性与股价崩盘风险之间呈现明显的正向相关性,尤其在稳定型机构分组中表现更为显著;2) 机构投资者在流动性和股价崩盘风险具有调节作用,稳定性机构投资者持股时更加显著;3) 进一步对二者作用机制的研究发现,机构投资者特别是稳定型机构投资者的中介作用显著。Based on the data of 880 A-share listed companies from 2008 to 2019, and considering the factors of heterogeneous institutional investors, this paper investigates the relationship between liquidity and the risk of stock price collapse. The results show that: 1) There is a significant positive correlation between liquidity and stock price collapse risk, especially when stable institutions are grouped;2) Institutional investors have a moderating effect on liquidity and stock price collapse risk, which is more significant when stable institutional investors hold shares;3) A further study on the mechanism of the two mechanisms shows that institutional investors, especially stable institutional investors, play a significant intermediary role.展开更多
基金Funded by the National Natural Science Foundation of China(No.52103285)the 111 National Project(No.B20002)。
文摘The nucleation and growth mechanism of nanoparticles is an important theory,which can guide the preparation of nanomaterials.However,it is still lacking in direct observation on the details of the evolution of intermediate state structure during nucleation and growth.In this work,the evolution process of bismuth nanoparticles induced by electron beam was revealed by in-situ transmission electron microscopy(TEM)at atomic scale.The experimental results demonstrate that the size,stable surface and crystallographic defect have important influences on the growth of Bi nanoparticles.Two non-classical growth paths including single crystal growth and polycrystalline combined growth,as well as,corresponding layer-by-layer growth mechanism along{012}stable crystal plane of Bi nanoparticles with dodecahedron structure were revealed by in-situ TEM directly.These results provide important guidance and a new approach for in-depth understanding of the nucleation and growth kinetics of nanoparticles.
文摘利用2008~2019年A股880家上市公司数据,考虑异质机构投资者的因素的情况下,考察流动性与股价崩盘风险之间的作用关系。研究表明:1) 流动性与股价崩盘风险之间呈现明显的正向相关性,尤其在稳定型机构分组中表现更为显著;2) 机构投资者在流动性和股价崩盘风险具有调节作用,稳定性机构投资者持股时更加显著;3) 进一步对二者作用机制的研究发现,机构投资者特别是稳定型机构投资者的中介作用显著。Based on the data of 880 A-share listed companies from 2008 to 2019, and considering the factors of heterogeneous institutional investors, this paper investigates the relationship between liquidity and the risk of stock price collapse. The results show that: 1) There is a significant positive correlation between liquidity and stock price collapse risk, especially when stable institutions are grouped;2) Institutional investors have a moderating effect on liquidity and stock price collapse risk, which is more significant when stable institutional investors hold shares;3) A further study on the mechanism of the two mechanisms shows that institutional investors, especially stable institutional investors, play a significant intermediary role.
