Fourier acceleration of iterative processes in disordered systems

Technical details are given on how to use Fourier acceleration with iterative processes such as relaxation and conjugate gradient methods. These methods are often used to solve large linear systems of equations, but become hopelessly slow very rapidly as the size of the set of equations to be solved increases. Fourier acceleration is a method designed to alleviate these problems and result in a very fast algorithm. The method is explained for the Jacobi relaxation and conjugate gradient methods and is applied to two models: the random resistor network and the random central-force network. In the first model, acceleration works very well; in the second, little is gained. We discuss reasons for this. We also include a discussion of stopping criteria.     

色散作用能的推导

对两个振动频率与极化系数不同的三维振子的色散作用能给出了一种简明的推导。     

HLS储存环束流发射度研究

 研究了合肥光源(HLS)储存环束流发射度与其长直线节消色散条件之间的关系；在考虑到H函数的匹配时，计算了储存环最低束流发射度；为光源多种运行模式提供了理论依据。     

Resonance frequencies and threshold gains of distributed feedback lasers with strong modulations

In this paper the calculation of resonance frequencies and threshold gains of distributed feedback (DFB) lasers with strong modulations is discussed. The theory is based on the Floquet solutions of a complex Hill differential equation. The dispersion relation of the above solutions is shown to be of importance for the behaviour of the resonances of the DFB laser.     

冷原子—无色散原子荧光光谱法测定奶粉中汞的有关问题的探讨

本文第一次提出汞样品经硝酸消化后，汞（Ｈｇ）与氮氧化物（ＮｘＯｒ）形成络合物，在经典的加氯化亚锡（ＳｎＣｌ２）还原时，生成Ｈｇ与ＮＯ并能同时逸出，确定了Ｈｇ与ＮｘＯｒ存在配位关系，对汞的测定在数学计量上增加到１．５倍，结果表明，应用五氧化二矾消化奶样品能如实反映这一关系，并精确地得出其汞含量，在联合国环境规划署和粮食农业及世界卫生组织食品污染联合监测计划的第八届铅，镉，汞的分析质量保证中，应用本法     

边界吸收效应对非定常剪切弥散的影响

采用延迟扩散方程［７，９］描述了具有边界吸收条件下，非定常剪切流动中的剪切弥散特性．给出了记忆函数、中心位移函数的控制方程．特例分析结果表明：所采用的模型方程是合理的；边界吸收效应使得纵向浓度分布具有后倾的趋势．这主要是由于边界吸收使得低速强剪切区浓度减少，剪切弥散贡献减少，从而污染物对流速度高于断面的平均速度．     

Three-Dimensional Analytical Models for Virus Transport in Saturated Porous Media

Analytical models for virus transport in saturated, homogeneous porous media are developed. The models account for three-dimensional dispersion in a uniform flow field, and first-order inactivation of suspended and deposited viruses with different inactivation rate coefficients. Virus deposition onto solid particles is described by two different processes: nonequilibrium adsorption which is applicable to viruses behaving as solutes; and colloid filtration which is applicable to viruses behaving as colloids. The governing virus transport equations are solved analytically by employing Laplace/Fourier transform techniques. Instantaneous and continuous/periodic virus loadings from a point source are examined.     

Distance—Stability of Nonlinear Discrete Systems

In this paper,the distance-sability of nonlinear discrete system is investigated by meansof the Gauss-Seidel iteration method.Some algebric criteria of the distance-stability are ob-tained.Construction of Lyapunov function is avoided.     

Effect of magnetic-field-induced torsion on neutrinos and supernova collapse

Summary The neutrino emission from supernova 1987A is being studied by taking into consideration the effect of the magnetic field present in the star. The magnetic field generates an anisotropic feature in the local space-time, which in turn leads to the cancellation of the axial-vector part of the neutrino current. The interaction cross-section of these neutrinos in the course of their interaction with matter on Earth has an inverse square energy dependence. The present work presents the calculations based on this changed cross-section that relates to predictions of the expected number of events at KAMIOKANDE on the basis of the Mont Blanc signal. It might be interesting to take a look into the implications of these results. The author of this paper has agreed to not receive the proofs for correction.