A novel approach of initial vectors construction in iterative target transformation factor analysis

The construction of the favorable initial iterative vectors is the key to iterative target transformation factor analysis (ITTFA). A tentative approach to construct the better initial vectors, which is based on the chromatographic information provided by evolving factor analysis (EFA), is proposed. A region, which contains the peak position at maximum height, is determined. Several elements in the region of each initial vector, instead of one element, are initialized as 1. The elements out of the region are initialized as 0. So it is not necessary to determine the exact peak position at maximum height for the resolution of partly overlapping chromatographic profiles, which may avoid the divergence brought by determination of the peak position at maximum height. In addition, it may give acceptable resolution for the embedded peaks. It is applied to resolve 2D-simulated data and experimental liquor GC/MS data, the resolutions are reasonable and improved.     

G -函数与迭代阵谱半径的估计

该文应用G -函数概念, 获得了迭代矩阵谱半径新的上、下界, 所得结果推广和改进了文献[1--6]中的相应结果.这些结果适合于更广泛的矩阵类, 数值结果也表明在相同的条件下这些新界优于文献[1--6]中的界.     

An Efficient Parallel ADI Algorithm for Turbomachinery Flows

The paper describes a domain decomposition strategy which allows high efficiency parallel simulations of turbomachinery flows. The implicit ADI parallel solver is based on the scalar approximate factorisation. The Navier-Stokes (NS) and turbulence model equations are discretised by centred finite differences. The results prove that the parallel calculations with domain decomposition, in which each sub-domain explicitly communicates with the adjacent ones at the end of each implicit iteration, may suffer from a considerable deterioration of the convergence rate. A simple sub-iterative domain recoupling strategy allows recovering the convergence rate of a single processor computation. The strategy is carefully analysed and optimised in terms of inter-processor data communication rate and algorithm memory requirements. The span-wise domain decomposition is particularly suited for turbomachinery flows and is applied to a radial impeller and to an axial turbine stator and stage to prove the validity and the accuracy of the proposed approach. The results indicate that the parallel recoupled algorithm usually reach efficiencies of 0.8, with peaks over 0.9 with up to 16 processors, thereby allowing a considerable speed-up of design and verification calculations.     

Quadrature Based Optimal Iterative Methods with Applications in High-Precision Computing

We present a simple yet effective and applicable scheme, based on quadrature, for constructing optimal iterative methods. According to the, still unproved, Kung-Traub conjecture an optimal iterative method based on $n+1$ evaluations could achieve a maximum convergence order of $2^n$. Through quadrature, we develop optimal iterative methods of orders four and eight. The scheme can further be applied to develop iterative methods of even higher orders. Computational results demonstrate that the developed methods are efficient as compared with many well known methods.     

改进三帧差分算法在移动物体检测中的应用

移动物体监控系统利用检测算法识别监控区域的移动物体,并进行实时异常信息存储,检测算法中的传统三帧差分法中的阈值是固定的,因此重叠部分无法准确检测出来,存在空洞现象,可能发生误判。针对这些问题,对已有的三帧差分法进行改进,结合图像边缘提取和自适应的迭代阈值计算方法来提高移动物体检测的准确性,并对异常信息进行选择性存储,由实验结果可知,应用平台采用改进后的移动物体检测算法,较好的提高了移动物体检测的灵敏度,增强了检测系统的实时性和准确性,若仅存储异常信息,可节省视频存储空间,并在定位异常动态信息时节省查找时间。     

纯相位菲涅尔全息图的反馈迭代算法及其硅基液晶显示

研究了纯相位菲涅尔计算全息图的制作方法,给出了一种生成纯相位菲涅尔计算全息图的算法.首先研究了菲涅尔衍射的数值模拟算法,分析了两种数值模拟算法的计算速度.将计算速度较快的菲涅尔衍射数值模拟算法和迭代算法相结合,并引入比例反馈,得到纯相位菲涅尔计算全息图的反馈迭代算法.其次,对比例反馈系数的选取进行了实验研究,得到其最优经验值范围,然后进行了仿真实验.仿真结果表明,该算法降低了重构误差,提高了全息图重构质量.最后基于新型空间光调制器反射型硅基液晶,建立了全息显示光电实验系统,对该算法进行了验证.     

Corrosion Behavior of Aluminum in Non‐Uniform Electric Fields

The present paper discusses the effect of the geometrical structure of the electric fieldon the corrosion of aluminum cathodes by electrolysis of aqueous solutions of sodium chloride. A correlation between the mass of the aluminum dissolved from the cathode and the factors electric current density, distance between the electrodes, electrolysis time and sodium chloride concentration by electrolysis with direct current in electric fields of various geometries was found.     

超线性收敛的指数下降迭代法

1　引　　言文[1]中借助于常微分方程的Liapunov方法建立了与非线性方程f(x)=0(1)在区间[a,b]内的解x*相对应的Cauchy问题dx/dt=-w(x)f(x)(2)x(0)=x0,　x0∈[a,b](3)其中f(x)在[a,b]上连续可导,f′(x)≠0,而w(x)满足w(x)f′(x)>0且使得Cauachy问题(2)—(3)的饱和解x=x(t,x0)存在唯一.于是非线性方程(1)在[a,b]内的解x*为自治系统(2)的渐近稳定的奇点,从而有limt→+∞x(t,x0)=x*,　　x0∈[a,b](4)成立.这说明对任一初值x0∈[a,b]通过解Cauchy问题(2)—(3)可得非线性方程(1)在[a,b]内的解x*.在文[2]中利用Lambert的非线性方法[3],导出了一个…     

鞍点问题迭代解法收敛因子估计

分析Ｂａｎｋ（１９９０年）的论文中的求解鞍点问题的迭代解法,得到一个改进的收敛因子估计。