基于个体策略选择的知识传播研究

本文采用小世界网络模型模拟现实组织结构,构建了组织内部基于个体策略选择的知识传播模型,探讨了个体策略选择和网络结构对组织内部知识传播效果的影响。研究发现组织中无条件传播知识的个体的数量与平均知识水平成正比,对知识传播起促进作用;在网络结构方面,小世界网络对知识传播更加有利;组织规模较小时,更换策略的时间间隔对知识传播有较大影响。研究结果为组织有效地促进知识传播提供了支持。     

Surface‐enhanced Raman spectra of individual multiwalled carbon nanotubes with small innermost diameters

The Raman spectra of individual multiwalled carbon nanotubes (MWCNTs) with the innermost diameters of 0.6–0.9 nm are studied by surface‐enhanced Raman scattering. The influences of small innermost diameters to Raman features are investigated. A clear and relatively sharp Raman peak appears at 1510 cm⁻¹ when the innermost diameter is close to 0.6 nm. Lorentzian fits of G band indicate that its splitting is affected by the small innermost diameter of MWCNT. Moreover, the splitting of 2iTO mode is also observed at 2800–3000 cm⁻¹. Copyright © 2012 John Wiley & Sons, Ltd.     

Dynamics of a Deterministic and Stochastic Susceptible-exposed-infectious-recovered Epidemic Model

We investigate a susceptible-exposed-infectious-recovered (SEIR) epidemic model with asymptomatic infective individuals. First, we formulate a deterministic model, and give the basic reproduction number $\mathcal{R}_{0}$. We show that the disease is persistent, if $\mathcal{R}_{0}>1$, and it is extinct, if $\mathcal{R}_{0}<1$. Then, we formulate a stochastic version of the deterministic model. By constructing suitable stochastic Lyapunov functions, we establish sufficient criteria for the extinction and the existence of ergodic stationary distribution to the model. As a case, we study the COVID-19 transmission in Wuhan, China, and perform some sensitivity analysis. Our numerical simulations are carried out to illustrate the analytic results.