在法拉第效应实验中不同光强点定位检测旋转角灵敏度的研究

通过实验验证马吕斯定律,并分别在消光位置和最大光强位置作检测点,测量介质的费尔德常数.根据实验结果的分析,讨论实验中普遍存在的"在光强极大值和光强最大相对变化率位置"检测灵敏度的问题,得出在消光位置测量线偏振光旋转角最精确的结论.     

Qualms concerning the inflationary scenario

It is shown that the release of the condition of adiabaticity is incompatible with the Einstein equations that are derived from the Robertson-Walker metric. Once dissipative processes are considered, the vanishing of the divergence of the mass-energy tensor is a combination of the first and second laws rather than being the relativistic analogue of the first law. Dissipative processes destroy isotropy and hence cannot be described by any standard model based on Robertson-Walker models.     

马氏过程函数的强大数定律

本文主要研究了马氏过程函数以及马氏环境中马氏链函数的强大数定律．     

Gap series and functions of bounded variation

Summary We prove that the gap seriesΣf(n _k x) does not behave like an independent random series when f is a function of bounded variation with rational discontinuity.     

滑动平均过程的Spitzer和Baum-Katz律的精确渐近

本文讨论了滑动和过程的Spitzer和Baum-Katz律的精确渐近,其中{ξ,ξi-∞相似文献   

On the heat flux vector for flowing granular materials—Part I: effective thermal conductivity and background

Heat transfer plays a major role in the processing of many particulate materials. The heat flux vector is commonly modelled by the Fourier's law of heat conduction and for complex materials such as non‐linear fluids, porous media, or granular materials, the coefficient of thermal conductivity is generalized by assuming that it would depend on a host of material and kinematical parameters such as temperature, shear rate, porosity or concentration, etc. In Part I, we will give a brief review of the basic equations of thermodynamics and heat transfer to indicate the importance of the modelling of the heat flux vector. We will also discuss the concept of effective thermal conductivity (ETC) in granular and porous media. In Part II, we propose and subsequently derive a properly frame‐invariant constitutive relationship for the heat flux vector for a (single phase) flowing granular medium. Standard methods in continuum mechanics such as representation theorems and homogenization techniques are used. It is shown that the heat flux vector in addition to being proportional to the temperature gradient (the Fourier's law), could also depend on the gradient of density (or volume fraction), and D (the symmetric part of the velocity gradient) in an appropriate manner. The emphasis in this paper is on the idea that for complex non‐linear materials it is the heat flux vector which should be studied; obtaining or proposing generalized form of the thermal conductivity is not always appropriate or sufficient. Copyright © 2006 John Wiley & Sons, Ltd.     

具有在位势的一维双原子链晶格振动的色散关系

在简谐近似下,求解具有在位势的一维双原子链晶格振动运动方程,得到了具有在位势的晶格振动的色散关系.在位势使色散关系声频支在布里渊区中心的振动频率不再为零,并且随在位势的增大而增大.对于原子之间相互作用势不随在位势大小变化的情况下,晶格振动的色散关系的频隙随在位势的增大而变宽.讨论了原子链由只有在位势的不连续极限(AC极限),通过在位势逐渐减弱而原子间相互作用势逐渐增强,最后演变到只有原子间相互作用势的原子链的情况.随着在位势减弱和相互作用势增强,色散关系的频隙由AC极限的孤立轻、重原子简谐振动频率之差逐渐变化到通常的无在位势的色散关系频隙.     

晶格振动色散关系与均匀杆纵振动色散关系的比较分析

一维单原子链晶格振动与均匀杆自由纵振动的运动方程在数学上存在内在的联系.将均匀杆自由纵振动运动方程中对空间的偏导数用差商代替,就得到一维单原子链晶格振动的运动方程.对于离散的一维单原子链晶格振动与连续的均匀杆自由纵振动的色散关系进行了比较分析.一维单原子链晶格振动的波矢具有特定的取值范围,即布里渊区,这是原子离散周期排布的结果.随着质量分布由离散逐渐向连续变化,一维单原子链晶格振动的色散关系逐渐演变为均匀杆纵振动的色散关系.     

Mathematical analysis of radionuclides displacement in porous media with nonlinear adsorption

This paper is devoted to the mathematical analysis of the miscible displacement of a set of radionuclides in a flow occurring in a heterogeneous porous medium. The flow is governed by Darcy's law, and the motion of the chemical species is given by a nonclassical advection-diffusion-reaction equations system. The novelty of the model lies in the adsorption phenomenon that leads to a time derivative of a nonlinear term in these equations. A semi-discretization method is used to establish the existence of weak solutions to this system. Uniform L^∞-estimates on the solutions are specified.     

Integration over quantum permutation groups

We find a combinatorial formula for the Haar measure of quantum permutation groups. This leads to a dynamic formula for laws of diagonal coefficients, explaining the Poisson/free Poisson convergence result for characters.