Hopf–Hopf bifurcation analysis based on resonance and non-resonance in a simplified railway wheelset model

Nonlinear Dynamics - This paper mainly investigates the dynamics of the non-resonant and near-resonant Hopf–Hopf bifurcations caused by the interaction of the lateral and yaw motion in a...     

Noise-induced phenomena in a versatile class of prototype dynamical system with time delay

Nonlinear Dynamics - This work presents a general class of prototype birhythmic dynamical systems, which can be extensively used to study the generation of complex bifurcation of limit cycles....     

含硫氨基酸与本征及缺陷石墨烯表面的相互作用

半胱氨酸及蛋氨酸是人体的两种含硫氨基酸,在生物活性中发挥着巨大的作用.本研究采用密度泛函理论方法对以上两种氨基酸在本征及缺陷石墨烯表面的吸附机理进行了详细研究.主要考虑了两种吸附体系:半胱氨酸及蛋氨酸平躺在两种石墨烯表面;两种氨基酸垂直地放置于两种石墨烯表面,且含硫的基团靠近表面.研究结果表明,半胱氨酸及蛋氨酸初始构型对它们之间的相互作用有一定的影响.两种氨基酸平躺时有较大的吸附能.此外,吸附能的结果显示两种氨基酸可以更好的与缺陷石墨烯表面紧密结合.同时,蛋氨酸与本征及缺陷石墨烯相互作用均大于半胱氨酸与本征及缺陷石墨烯相互作用.模拟结果有望为含硫氨基酸的石墨烯传感器提供有用的指导.     

蓝宝石冲击消光晶向效应的第一性原理

蓝宝石的冲击消光现象是高压领域中的研究热点.低压段(86 GPa范围内)的实验研究表明蓝宝石的冲击消光与晶向相关,但在高压段(压力范围:131255 GPa)是否也具有晶向相关性目前尚不清楚.为此,利用第一性原理方法,分别计算了八个不同晶向的蓝宝石理想晶体和含氧离子空位缺陷晶体在高压段的光吸收性质,结果发现:1)蓝宝石在高压段的冲击消光表现出明显的晶向效应,且该效应还随压力增大而增强;一步的数据分析可以看出,在冲击实验采用的波段内,a晶向的消光最弱(透明性最好),c晶向的消光最强与c晶向的消光接近,g晶向的消光要弱于s晶向的消光.鉴于此,如果在高压段开展加窗冲击波实验,建议选择a晶向或m晶向的蓝宝石作为其光学窗口.本文结果不仅有助于深入地认识蓝宝石在极端条件下的光学性质,而且对未来的实验研究有重要的参考作用.     

Reduction in the $$\mathbf {(4+1)}$$(4+1)-dimensional Fokas equation and their solutions

Nonlinear Dynamics - An integrable extension of the Kadomtsev–Petviashvili (KP) and Davey–Stewartson (DS) equations is investigated in this paper. We will refer to this integrable...     

Vitamin K1 distribution following intravenous vitamin K1–fat emulsion administration in rats

This study investigated vitamin K₁ (VK₁) distribution following intravenous vitamin K₁–fat emulsion (VK₁–FE) administration and compared it with that after VK₁ injection. Rats were intravenously injected with VK₁–FE or VK₁. The organ and tissue VK₁ concentrations were determined using high‐performance liquid chromatography method at 0.5, 2 and 4 h to determine distribution, equilibrium and elimination phases, respectively. In the VK₁–FE group, the plasma, heart and spleen VK₁ concentrations decreased over time. However, other organs like liver, lung, kidney, muscle and testis, reached peak VK₁ concentrations at 2 h. In the VK₁ injection group, the liver VK₁ concentrations were significantly higher than those in other organs at the three time points. However, VK₁ concentrations in the other organs peaked at 2 h. In addition, in VK₁–FE group, the heart, spleen and lung VK₁ concentrations were significantly higher than those in the VK₁ injection group at the three time points, and the liver VK₁ concentration was significantly higher than that in the VK₁ injection group at 4 h. The VK₁ amount was greatest in the liver compared with the other organs. Thus, the liver is the primary organ for VK₁ distribution. The distribution of VK₁ is more rapid when injected as VK₁–FE than as VK₁. Copyright © 2015 John Wiley & Sons, Ltd.