椭圆轨道真近点角的级数计算方法

用级数展开方法得到真近点角超越方程,由迭代法求真近点角与时间的关系,讨论迭代收敛的充分条件．对于不满足迭代收敛充分条件情形,列写偏近点角超越方程,用迭代法求偏近点角变化规律,用数值积分方法求出真近点角与时间的关系,指出所有椭圆轨道都满足偏近点角迭代收敛的充分条件．讨论小偏心率椭圆轨道真近点角近似超越方程,由迭代法求真近点角与时间的关系．数值模拟结果表明该方法的有效性．     

Mechanical analysis of orbit tracking movement of feed system in large spherical radio-telescope

The curve equation and its mechanics analysis of suspended-cable under the condition of end load are given. Then on the basis of it, the mechanical analysis of suspended-cable system for large spherical radio-telescope is studied, and procedures of the control for the orbit tracking movement of the line feed in large spherical radiotelescope are given. The validity of the results mentioned above is confirmed by means of computer simulations.     

PO反应中混沌控制的变量交叉反馈方法研究

The variable cross feedback（VCF）method is proposed to control the nonlinear chaos system. The control principle is introduced,and the Peroxidase-Oxidase（PO）system is taken as a typical example to demonstrate the effectiveness of this method. The dynamical behaviors of the PO system controlled using the VCF method are given by computer numerical simulation. The results show that the return map of the system can be changed into the finite isolated points from the assemblage of discrete points having regular distribution and structure by appropriately     

混沌系统的变量变化率反馈控制方法研究

设计了一种控制连续非线性系统中混沌的新方法--变量变化率脉冲反馈(VRPF)方法.介绍了VRPF方法的控制原理以及反馈系数和脉冲间隔的选择技巧.将此方法应用到BZ反应3D模型系统混沌的控制中,计算机仿真模拟显示,通过恰当地选择反馈系数和脉冲间隔,可以将系统稳定在1p、2p、3p、4p、…、2n×3mp (n、m为整数)这样不同的周期轨道,从而使系统的功率谱也由混沌态时的连续谱转变为具有分立单峰的分立谱.此外,仿真模拟还发现VRPF方法具有极宽的控制域.     

Solitary Wave in Linear ODE with Variable Coefficients

In this paper, the linear ordinary differential equations with variable coefficients are obtained from thecontrolling equations satisfied by wavelet transform or atmospheric internal gravity waves, and these linear equationscan be further transformed into Weber equations. From Weber equations, the homoclinic orbit solutions can be derived,so the solitary wave solutions to linear equations with variable coefficients are obtained.     

Chaotic belt phenomena in nonlinear elastic beam

IntroductionThechaoticphenomenainsolidmechanicsfieldsbringmoreandmoreinterest.In 1 998,F .C .Moon[1]analyzedthechaoticbehaviorsofbeamsexperimentallyfirst.Thenhestudiedthedynamicsresponseoflinearelasticbeamsubjectedtransverseperiodicload .Thechaoticmotionsoflineardampingbeamshavebeenstudiedbymanyscholarsathomeandabroadinrecentyears[2 ,3].ThedynamicbehaviorsofnonlineardampingbeamssubjectedtotransverseloadP=δP0 (f+cosωt)sin(πx/l)arestudiedinthispaper.Thecriticconditionsthatchaosoccursinthes…     

Parametric finite-volume micromechanics of periodic materials with elastoplastic phases

The recently incorporated parametric mapping capability into the finite-volume direct averaging micromechanics (FVDAM) theory has produced a paradigm shift in the theory’s development. The use of quadrilateral subvolumes made possible by the mapping facilitates efficient modeling of microstructures with arbitrarily shaped heterogeneities, and eliminates artificial stress concentrations produced by the rectangular subvolumes employed in the standard version. Herein, the parametric FVDAM theory is extended to the inelastic domain by implementing additional formulation required to accommodate plastic and thermal loading. Two different approaches of implementing plasticity have been investigated. The first approach is based on the treatment employed in previous versions of the theory wherein plastic strain fields are represented by a series expansion in Legendre polynomials. The second approach is based on direct surface-averaging of plastic strains calculated at a number of collocation points along the quadrilateral subvolumes’ surfaces, and offers substantial simplification in the parametric finite-volume theory’s elastic–plastic framework. Moreover, substantial reductions in execution times without loss of accuracy are realized due to the elimination of redundant plastic strain calculations in the subvolumes’ interiors employed in the evaluation of the Legendre polynomial coefficients. Numerical studies demonstrate the advantages of the parametric FVDAM theory relative to the standard version, together with new results that highlight its modeling capabilities vis-a-vis an emerging class of periodic lamellar materials with wavy microstructures and the thus-far undocumented architectural effects amplified by plasticity.     

On the number of limit cycles in double homoclinic bifurcations

LetL be a double homoclinic loop of a Hamiltonian system on the plane. We obtain a condition under whichL generates at most two large limit cycles by perturbations. We also give conditions for the existence of at most five or six limit cycles which appear nearL under perturbations.     

一种航天器天文自主定轨方法

提出用星敏感器和地平仪测量星光角距作为主要观测量,用地平仪直接测量得到地心方向矢量,用间接测得的地心距离作为补充观测量,并用推广卡尔曼滤波方法来实时确定航天器的轨道。文中对系统的构成、模型的建立、以及卡尔曼滤波的方法都作了认真的仿真研究,并获得了满意的结果。     

Resonant Homoclinic Flip Bifurcations

This paper studies three-parameter unfoldings of resonant orbit flip and inclination flip homoclinic orbits. First, all known results on codimension-two unfoldings of homoclinic flip bifurcations are presented. Then we show that the orbit flip and inclination flip both feature the creation and destruction of a cusp horseshoe. Furthermore, we show near which resonant flip bifurcations a homoclinic-doubling cascade occurs. This allows us to glue the respective codimension-two unfoldings of homoclinic flip bifurcations together on a sphere around the central singularity. The so obtained three-parameter unfoldings are still conjectural in part but constitute the simplest, consistent glueings.