计算机组成原理实验仪的设计及实现

就一种用 80 31单片机控制的计算机组成原理实验仪的设计及实现进行了详细论述。     

一种测定大值的风速计

简单叙述了研制1种大风速值简易精密测量仪器原理和方法，并对测量误差进行了估算。     

某型卫星测试转台俯仰翻转丝杠动力学分析

以某型卫星测试转台俯仰机构为研究对象,在ADAMS中建立了虚拟样机,得到了在翻转过程中丝杠轴向力曲线,并将仿真结果与理论计算结果及试验结果进行比较,验证了虚拟样机建模的合理性;研究结果为同类物理样机设计中滚珠丝杠的选用校核,台体框架的设计校核以及机电联合仿真提供有利数据支撑。     

Dynamics and Composition of Rings

Planetary rings are found around all four giant planets of our solar system. These collisional and highly flattened disks exhibit a whole wealth of physical processes involving dust grains up to meter-sized boulders. These processes, together with ring composition, can help understand better the formation and evolution of proto-satellite and proto-planetary disks in the early solar system. The present chapter reviews some fundamental aspects of ring dynamics and composition. The forthcoming exploration of the Saturn system by the Cassini mission will bring both high resolution and time-dependent information on Saturn’s rings.     

PC-index fluctuations and intermittency of the magnetospheric dynamics

One minute resolution Polar Cap (PC) index was used for the analysis of magnetospheric dynamics. The 1995–2000 time series analysis revealed that the power spectrum of the PC-index fluctuations is a power law in a wide range of frequencies. However, the obtained exponents differ for low and high frequency regions. The probability distribution functions of the PC-index fluctuations show a strong non-gaussian shape, depending on the time of increment. This indicates that the PC-index exhibits intermittency, previously detected in solar wind and auroral electrojet index fluctuations. The PC-index probability distribution functions were fitted by the functional form proposed by Castaing et al. [Velocity probability density functions of high Reynolds number turbulence. Physica D. 46, 177–200, 1990] to describe intermittency phenomena in ordinary turbulent fluid flows. The agreement between the fitting parameters obtained for the PC index and those reported before for solar wind magnetic field fluctuations is within 30%; which is noticeably less than the difference between the same parameters of solar wind and the AE-index fluctuations. This fact indicates that the PC index reflects the solar wind influence on the high-latitude magnetosphere, especially during the summer.     

Modeling Multifractality of the Solar Wind

The question of multifractality is of great importance because it allows us to investigate interplanetary hydromagnetic turbulence. The multifractal spectrum has been investigated with Voyager (magnetic field) data in the outer heliosphere and with Helios (plasma) data in the inner heliosphere. We use the Grassberger and Procaccia method that allows calculation of the generalized dimensions of the solar wind attractor in the phase space directly from the cleaned experimental signal. We analyze time series of plasma parameters of the low-speed streams of the solar wind measured in situ by Helios in the inner heliosphere. The resulting spectrum of dimensions shows a multifractal structure of the solar wind attractor. In order to quantify that multifractality, we use a simple analytical model of the dynamical system. Namely, we consider the generalized self-similar baker’s map with two parameters describing uniform compression and natural invariant measure on the attractor of the system. The action of this map exhibits stretching and folding properties leading to sensitive dependence on initial conditions. The obtained solar wind singularity spectrum is consistent with that for the multifractal measure on the weighted baker’s map.     

A Thermodynamic Approach to the Magnetospheric Complexity: The Role of Fluctuations

Recent studies evidenced that the magnetotail dynamics looks like the one of an avalanching system. This fact has been related with a near criticality dynamics and modelled by singular diffusion and transport equations. Here, we discuss some features of the Earth’s magnetotail dynamics using a thermodynamic approach. In detail we discuss the role played by fluctuations in singular diffusion and relaxation processes from a non-equilibrium thermodynamics point of view. Moreover, the emergence of non-Gaussian statistics is discussed in the framework of the thermodynamics of composite systems.     

航天器弹性附件伸展动力学研究

利用动量矩定理推导出带伸展弹性板航天器的姿态动力学方程，在弹性板等速伸展的情况下，导出板的振动与伸展运动耦合微分方程，航天器姿态运动与板的伸展运动、振动耦合微分方程，通过龙格－库搭积分法得出了数值解，结果表明：弹性板等速伸展时，其振动的振幅随板长度的增长而增大，航天器姿态角速度随板长度的增长而减少。弹性板等速率越大，板振动的振幅越大。     

煤气管道费用的动态规划模型

本文针对铺设管道的费用问题。有效利用最优化原理，建立合适的动态规划模型。使其总费用最少。