A Hierarchy of Integrable Nonlinear Lattice Equations and New Integrable Symplectic Map

A discretespectral problem is discussed.and a hierarchy of integrable nonlinear lattice equations related to this spectral problem is devised.The new integrable symplectic map and finite-dimensional integrable systems are given by nonlinearization method.The binary Bargmann constraint gives rise to a Baecklund transformation for the resulting integrable lattice equations.     

格子Boltzmann亚格子模型的研究

为了将格子Boltzmann法应用于大雷诺数流动的模拟,本文将Smagorinsky亚格子模型和LBGK模型相结合,并对该亚格子LBM模型进行了研究。利用该亚格子LBM模型,对二维顶盖驱动流进行了模拟,得到了若干大雷诺数下流线图和方腔中心线上无量纲速度分布。计算结果与基准解进行比较,两者相互吻合。     

耦合映象格子时空行为的电路仿真实验

设计以一维逻辑斯蒂离散电路作为元胞子电路的耦合格子时空电路系统,利用PSPICE仿真平台,观测到该电路系统存在的各种时空动力学行为.仿真实验结果与计算机数值计算结果一致.     

Moving Compacton—like Kink in a Purely Anharmonic Lattice with Symmetric On—Site Potential

We study the moving compacton-like kink in the system of a purely anharmoinc lattice with symmetric onsite poential by a direct algebraic method.It is found that the localization of the compactons is related to the nonlinear coupling parameter Cnl and the potential barrier height V0 of the double well potential,and the velocity of the propagation of the compacton is determined by the localization parameter q and the potential barrier height V0.Numerical calculation results demonstrate that the compacton is stable when it moves along the lattice chain.     

建议恢复"lattice"的并列译名"点阵、格子"

最近，中国物理学会第8届名词工作委员会在《物理》2005年3期228页发表文章，希望“大家都来关心物理学名词工作”，同时《物理》还发表王正行教授的文章，建议“测不准”与“不确定”二词并用，本文响应上述号召，提出恢复“lattice”的并列译名“点阵、格子”的建议，供这一届名词工作委员会参考。     

对三量纲制的讨论

 物理量是在量度物质属性和描述物质运动状态时所用的各种量值,最基本的物理量有时间、长度、质量、温度、电流强度、物质的量和发光强度,其余的物理量则是按它们各自的定义由基本物理量组合而成;量纲是用于表示一个物理量怎样由基本量(包括这些量的幂指数)组合的式子,量纲的原始含义是测量,它只是表明物理量的性质而不表明其大小,因此量纲只是用于定性地描述物理量,在动力学领域,人们选定长度L、质量M及时间T作为基本量纲,也称三量纲制。为什么取三量纲制?能不能取更少的量纲?二量纲制、一量纲制甚至无量纲制,会给物理世界带来什么样的影响呢?     

格子-BOLTZMANN方法非均分网格的实施

本文提出了格子-Boltzmann方法的一种新的插值算法,使得网格划分与微观粒子运动方向相分离;用该方法模拟了后台阶通道内的突扩流动和二维极坐标下的空腔流.所得结果与传统方法吻合良好,证明了该方法的可行性.     

Lattice QCD Production on a Commodity Cluster at Fermilab

Large scale QCD Monte Carlo calculations have typically been performed on either commercial supercomputers or specially built massively parallel computers such as Fermilab‘s ACPMAPS.Commodity clusters equipped with high performance networking equipment present an attractive alternative,achieving superior performance to price ratios and offering clear upgrade paths.We describe the construction and results to date of Fermilab‘s prototype production cluster,which consists of 80 dual Pentium Ⅲsystems interconnected with Myrinet networking hardware.We describe software tools and techniques we have developed for operating system installation and administration.We discuss software optimizations using the Pentium‘s built-in parallel computation facilities(SSE),Finally,we present short and long term plans for the construction of larger facilities.     

Some Conditions for Matrices over an Incline To Be Invertible and General Linear Group on an Incline

Inclines are the additively idempotent semirings in which products are less than or equal to either factor. In this paper, some necessary and sufficient conditions for a matrix over L to be invertible are given, where L is an incline with 0 and 1. Also it is proved that L is an integral incline if and only if GLn（L） = PLn （L） for any n （n 〉 2）, in which GLn（L） is the group of all n × n invertible matrices over L and PLn（L） is the group of all n × n permutation matrices over L. These results should be regarded as the generalizations and developments of the previous results on the invertible matrices over a distributive lattice.     

热声热机声场的格子气分析

从格子气自动机演化方程恢复了宏观热声方程,采用D2Q9热格子气模型模拟热声热机系统的压力场、温度场和速度场,获得压力驻波的传播和反射过程。模拟结果显示,在所给模拟条件下压力波具有非线性的特征,变截面附近的流场区域会产生引起非线性耗散的涡流。本文也分析了谐振管几何尺寸及格子气粒子密度对系统频率和压力的影响,验证了热声热机格子气模型的有效性。