双面理想完整约束系统的机械能守恒律

 研究双面理想完整约束系统在约束不是定常且主动 力不是有势时的机械能守恒律. 建立系统的能量变化方程, 给出存在机械能守恒律的充分必要条件. 分析有机械能守 恒律的12种情况. 最后给出说明性算例.     

Onthe Rosen-Edelstein model andthe theoretical foundation of nonholonomicmechanics

A new model in nonholonomic mechanics,the Rosen--Edelstein model, has been studied. We prove that the new model is a Lagrange problem in which the action integral $\int^{t_{1}}_{t_{0}}L\dd t$ can be made stationary.The theoretical basis of nonholonomic mechanics is investigated and discussed. Finally, we give the range of practical applications of theRosen--Edelstein model.     

Film Thickness Dependence of Rectifying Properties of La1.85Sr0.15CuO4/Nb-SrTiO3 Junctions

In this work, p-n junctions are made from directly depositing optimal doped La1.85Sr0.15CuO4 （LSCO） films on n-type Nb-doped SrTiO3 substrates. Film thickness controlled rectifying behaviors are strikingly displayed. The starting points of the diffusion voltage reduction Vd-on change clearly with varying film thickness. Vd-on and Tc coincide with each other when the film thickness is larger than 300 nm, indicating a close relation between the two parameters. However, when the film is very thin （〈 350 nm） a departure between the two parameters was also observed. A possible reason for this is discussed within the framework of an inhomogeneous Sehottky contact. Enhanced interface inhomogeneity due to the tensile strain appears to be the origin.     

广义Birkhoff自治系统平衡状态的流形稳定性

研究广义Birkhoff自治系统平衡状态流形稳定性.建立广义Birkhoff自治系统的受绕运动方程和平衡方程.由Liapunov稳定性理论给出广义Birkhoff自治系统的平衡状态流形稳定性的有关判据.举例说明结果的应用.     

An inverse problem in analytical dynamics

This paper presents an inverse problem in analytical dynamics. The inverse problem is to construct the Lagrangian when the integrals of a system are given. Firstly, the differential equations are obtained by using the time derivative of the integrals. Secondly, the differential equations can be written in the Lagrange equations under certain conditions and the Lagrangian can be obtained. Finally, two examples are given to illustrate the application of the result.