Efficiency of numerical integration algorithms related to divisor theory in cyclotomic fields

For function classes with dominant mixed derivative and bounded mixed difference in the metric ofL ^q (1<q≤2), quadrature formulas are constructed so that the following properties are achieved simultaneously: the grid is simple, the algorithm is efficient and close to the optimal algorithm for constructing the grid, and the order of the error on the power scale cannot be further improved. The caseq=2 was studied earlier. Translated fromMatematicheskie Zametki, Vol. 61, No. 2, pp. 297–301, February, 1997. Translated by N. K. Kulman     

合肥国家同步辐射源X射线束时间相干长度的估算

报道了合肥国家同步辐射实验室软Ｘ射线束的时间相干长度的理论估算，方法和实验结果。     

一种新的半导体材料和器件结构:COS

国际半导体技术发展进程表预期器件的特征尺寸不久将减小到0.1μm以下，SiO2作为MOS器件栅介质遇到不可克服的困难，人们在寻找新的栅介质材料时，提出一种新的结构，称为半导体上的晶态氧化物（COS），最近，COS被用作Si衬底上生长GaAs的过渡层，成为半导体材料和器件发展中一项新的突破，文章对这一结构的进展情况做一简要介绍。     

对振荡函数数值积分方法的进一步探讨

本文在 [1 ]等成果的基础上 ,对振荡函数数值积分的方法做了进一步的探讨 ,给出了一种代数精确度更高、具有函数振荡越剧烈求积结果越精确的特点的、优于 [1 ]的新的对振荡函数的 Gauss型积分 .     

曲线搜索的有关理论与数值方法

统一表达了无约束优化问题下降曲线的常微分方程组．证明了两个常见的方程组实质上是参数不同的同一曲线．指出并证明了一种方程组是有利于数值计算的．本文还提出了两个算法一基于积分的搜索法和附加插值法．研究表明曲线寻优与累积迭代信息的策略可以提高优化算法的效率和稳定性．借助于对偶规划本方法对约束优化问题也获得了效率．     

Mathematical Programming Techniques in Constraint Programming: A Short Overview

In recent years, the integration of techniques from Artificial Intelligence and Operations Research has shown to improve the solutions of complex and large scale combinatorial optimization problems, in terms of efficiency, scalability and optimality. In this context, Constraint Programming is an emerging discipline situated at the confluence of the two fields that has been recognized as a suitable environment for achieving such an integration. This paper briefly presents the integration directions explored in the literature, and provides some pointers to relevant work in these directions.     

The generating functional for the probability density functions of Navier-Stokes turbulence

A generating functional for the equal-time spatial probability density functions which represent the ensemble of turbulent incompressible Navier-Stokes fluids is introduced. By formally solving the linear evolution equation satisfied by this functional, the probability densities are represented as functional integrals. It is shown that the generating functional can be regarded as the space characteristic functional of a generalized random field defined on the phase space spanned by the material position and velocity fields of a fluid particle. The interpretation of this random field, which satisfies a dynamical equation similar to Vlasov's, is clarified through the formal analogies between the statistics of molecules and fluid particles at the functional level. A class of statistically realizable and solvable models is also considered within the context of the present formalism.     

非均匀二型三角剖分二元二次样条的数值积分公式

给出了构成矩形域的4个三角形子区域的二元样条拟插值算子的等价形式,对这4个三角形子区域分别建立了数值积分公式,相加后得到一般矩形域上的数值积分公式,同时给出了构造数值积分公式所需的结点处的函数值与相应的求积系数。进一步,利用算子范数、连续模及拟插值算子的保多项式性,针对具有不同连续性的被积函数,得到了相应的数值积分公式的求积余项。研究表明,提出的数值积分公式不仅具有较高的计算精度,而且计算量约为二元张量积型求积公式的1/5。数值算例进一步说明了数值积分公式的有效性。     

RDX(210)单晶准等熵压缩实验的数值分析

基于准等熵压缩实验,建立了考虑线弹塑性效应的反积分数学模型,并针对Sandia的含能材料RDX(210)的无反应准等熵压缩实验数据,进行了数值模拟和分析.结果表明,本文模型可以恰当地描述该含能材料的准等熵压缩实验过程,可以得到与文献结果吻合较好的样品加载速度历史;计算得到了样品内部任意位置直至加载面上的信息、应力应变和...     

不同GPS/SINS超紧组合框架的分析与等价性推导

GPS和SINS的组合导航系统是实现连续、准确定位的有效方式之一,尤其二者的超紧组合导航方式,在解决GPS接收机的抗干扰和抗动态性能方面效果显著。分别针对基于GPS的I、Q信号层次数据融合的超紧组合结构和惯性信息辅助的超紧组合结构进行分析,在将惯性信息辅助结构演化为联邦形式的组合结构的基础上,对涉及其中的不同组合滤波的状态方程和量测方程深入研究。利用集成和联邦卡尔曼滤波器之间的关系,完成不同超紧框架的趋同等价性证明。仿真结果初步表明,相同初始条件下不同组合方法在定位精度方面具有一致性。