分步逼近计算法在分析摩擦铰链窗运动状况中的应用

摩擦铰链运动轨迹复杂,没有完备的使用指导和说明,目前只能凭经验或实物实验手段来判断使用摩擦铰链窗的运动是否存在干涉状况,给此类门窗的设计和使用带来众多不便。本文针对这一问题,将数学分析中常用的分步逼近计算法应用在摩擦铰链门窗的运动分析中,使摩擦铰链窗的各种干涉分析变得简便实用,使长期困扰设计人员和使用厂家的问题迎刃而解。

惯性定位测量重力空间参数的逼近计算与工程实践

针对我国惯性定位测量的现状,根据地面重力异常与地形数据密的强相关特性,研究探讨了利用高分辨率地球重力场扰动位模型和地形数据快速求取重力空间参数的计算模型,并通过工程实践证明了其实用性,对实现惯性测量完整定位具有重要的应用价值。

CCD位移传感器结构参量计算方法

推导了 CCD位移传感器的计算公式 ,给出了一种位移传感器结构参量的数值逼近计算方法 ,实验结果表明 ,利用该方法确定 CCD位移传感器的结构参量 。

基于六次B样条的计算方法

基于偶次B样条基函数的一般构造方法,通过时域的细分划重构,拓展和构造了均匀分划的六次B样条函数及其基函数,并在此基础上,推导了结构动力响应计算中的位移元子区间法嵌套方法的递推格式,分析了该递推格式的稳定性,计算了该基函数在梁弯曲中的应用。结构的动静力计算表明,六次B样条基函数表征的物理概念清晰、简洁,表明该基函数具有良好的逼近性能和适应性,同时也表明偶次B样条应用的可行性。通过力学方法获得的六次B样条的成果,属于逼近理论的基础部分,可应用于需要逼近计算的诸多领域。

梯形明渠均匀流水深和底宽的简捷计算法

介绍的简捷法（逼近法）具有计算式结构简明，计算方便等特点，精度可随逼近次数增多而增高，可满足设计的任何精度要求。

展开定理的补充和偶次B样条基函数

在均匀分划的B样条展开定理中,奇次B样条以整数点展开,而对偶次B样条将如何展开,展开定理并未说明.通过时域的逼近计算,补充了偶次B样条在展开定理中的展开方式,提出了其基函数的一般构造方法.应用四次B样条基函数计算梁的弯曲,表明了偶次B样条展开方式的合理性,同时也表明了该基函数有较佳的逼近性能和适应性.研究成果属于逼近理论的基础部分,可以应用于需要逼近计算的诸多领域.

水轮机特性曲线的三次B样条拟合及优化

针对传统B样条对水轮机特性曲线拟合精度较低的现状,提出采用优化的三次B样条曲线对水轮机模型综合特性曲线进行逼近计算,利用像素单位转化及正交投影误差判断处理数据,取得了良好的曲线拟合效果。对等效率闭合曲线HL240D41_CurveID_42数据的拟合,验证了该方法可行有效。

泰勒级数在数值法中的应用

图示法求解具有给定X和Y初值的常微分联立方程组: (dx)/(dt)=F(x,y,t) (dy)/(dt)=G(x,y,t)

Decoherence of Entangled States Calculated by a Systematic Approximate Method

In this paper the coherent-state approximation （CA） method is used to deal with the problem of the decoherence of the entangled states of two two-state systems. As the base of the discussion, the dissipation of one two-state system has been investigated at first. The improved results calculated by CA are given in the paper. It is shown that the right approaching behavior and scaling law have been obtained when CA is applied to the problem of dissipation of two two-state systems coupled with environment. The whole evolution process and calculated results of the decoherence of the entangled states show also the scaling law, right approaching behavior, and rich phenomenon.

Effect of approach run velocity on the optimal performance of the triple jump

Purpose： The purpose of this study was to determine the effect of horizontal and vertical velocities at the landing of the last step of approach run on the performance and optimal phase ratio of the triple jump. Methods： Three-dimensional kinematic data of 13 elite male triple jumpers were obtained during a competition. Computer simulations were performed using a biomechanical model of the triple jump to determine the longest actual distance using the optimal phase ratio with altered horizontal and vertical velocities at the landing of the last step of approach run. Results： The actual distance obtained using the optimal phase ratio significantly increased as the horizontal velocity at the landing of the last step of approach run increased （p = 0.001） and the corresponding downward vertical velocity decreased （p = 0.001）. Increasing horizontal velocity at the landing of the last step of approach run decreased optimal hop percentage and increased optimal jump percentage （p = 0.001）, while decreasing corresponding downward vertical velocity increased optimal hop percentage and decreased optimal jump percentage （p = 0.001）. Conclusion： The effects of the velocities at the landing of the last step of approach run on the optimal phase ratio were generally small and did not qualitatively alter optimal techniques.

加速射频电磁场辐射抗扰度实验校准的方法

本文提出了一种辐射电磁场抗扰度测试校准标准实验场的方法—“计算逼近法”。这种方法根据天线理论,推导出信号发生器输出电平与观测点场强之间的关系,并做了实际测量,以此为基础,提出“计算逼近法”校准测试场,开发了辐射电磁场抗扰度自动测试软件。用此方法,可以大大提高校准速度,缩短校准时间,提高测试效率。

A quadratic programming method for optimal degree reduction of Bézier curves with G^1-continuity

This paper presents a quadratic programming method for optimal multi-degree reduction of B6zier curves with G^1-continuity. The L2 and I2 measures of distances between the two curves are used as the objective functions. The two additional parameters, available from the coincidence of the oriented tangents, are constrained to be positive so as to satisfy the solvability condition. Finally, degree reduction is changed to solve a quadratic problem of two parameters with linear constraints. Applications of degree reduction of Bezier curves with their parameterizations close to arc-length parameterizations are also discussed.

Adomian Decomposition Method and Padé Approximants for Nonlinear Differential-Difference Equations

Combining Adomian decomposition method （ADM） with Pade approximants, we solve two differentiaidifference equations （DDEs）： the relativistic Toda lattice equation and the modified Volterra lattice equation. With the help of symbolic computation Maple, the results obtained by ADM-Pade technique are compared with those obtained by using ADM alone. The numerical results demonstrate that ADM-Pade technique give the approximate solution with faster convergence rate and higher accuracy and relative in larger domain of convergence than using ADM.

A Study on Simple Prediction Method of Heat Load： A Use of Linear Approximation Indicial Response in Basements

This study was conducted to establish a predictable method for a heat load of an underground structure with sufficient accuracy. As the first step, our previous paper reported the measurement results of field experiments on an underground experimental basement under internal heat generation conditions. Also, it presented the results of numerical analyses on the heat and moisture behavior and the influence of internal heat generation of the experimental basement and ground. However, it is practically impossible to utilize the model of simultaneous heat and moisture transfer at the design phase because the prediction by the model of simultaneous heat and moisture transfer requires a long calculation time. In this paper, the authors present the simple load calculation technique, using a linearized approximation indicial response of the inner surface heat flux in a basement to outdoor air temperature change. In addition, the approximation indicial responses for each part of the single-walled concrete drawn using this technique are arranged. The heat load calculation example of application to the basement of the optional size by this technique is shown.

Modified Kantorovich Operators Providing a Better Error Estimation

Abstract： The approximation operator for every kind of the objective function is different in approximation theory. For Lebesgue function, we introduce a kind of modified Kantorovich operators, which preserve the test functions 1 and x2. This type of modification enables better error estimation on the interval[＋√3/3,＋∞] than the classic ones. Finally, a Voronovskaya-type theoremfor these operators is also obtained.

Estimates of Central Moments for One Kind of Exponential-Type Operators

In this paper,the explicit estimates of central moments for one kind of exponential-type operators are derived.The estimates play an essential role in studying the explicit approximation properties of this family of operators.Using the proposed method,the results of Ditzian and Totik in 1987,Guo and Qi in 2007,and Mahmudov in 2010 can be improved respectively.

NEW FAST ALGORITHM FOR 2-D ANGLE-OF-ARRIVAL ESTIMATION

Based on propagator method, a fast 2-D Angle-Of-Arrival (AOA) algorithm is proPosed in this paper. The proposed algorithm does not need the Eigen-Value Decomposition (EVD) or Singular Value Decomposition (SVD) of the Sample Covariance Matrix (SCM), thus the fast algorithm has lower computational complexity with insignificant performance degradation when comparing with conventional subspace approaches. Furthermore, the proposed algorithm has no performance degradation. Finally, computer simulations verify the effectiveness of the proposed algorithm.

“说了算”不如“算了说”——摭谈定量计算法在高中物理教学中的应用

学生对概念规律的深度理解不能只停留在定性分析层面,很多时候必须借助定量计算来进一步加深理解。培养学生的科学思维也不应该是纯理性的或全抽象的,定量计算往往可以让学生的科学思维变得感性和具象。指导学生完成科学探究的过程固然很有意义,但是帮助学生发现需要探究的问题更有价值,而很多隐性的问题是可以指导学生通过定量计算来发现的。

基于七次B样条的结构分析方法

通过展开空间基的等价性,构造了均匀分划的七次B样条基函数的表达式。结构的动静力计算表明该基函数表征的物理概念清晰、简洁,表明该基函数具有良好的逼近性能和适应性,同时也表明高次B样条应用的可行性。基于子区间法的基本思想和方法,推导了基于均匀分划的七次B样条的子区间法递推格式。该递推格式虽然为条件稳定,适用于有限维的动力响应计算,同时也适用于无限维的无条件稳定。动力响应递推格式的实现拓展了新的计算方法和途径。通过力学方法获得的七次B样条的成果,属于逼近理论的基础部分,可以应用于需要逼近计算的诸多领域。

h-P Finite Element Approximation for Full-Potential Electronic Structure Calculations

The(continuous) finite element approximations of different orders for the computation of the solution to electronic structures were proposed in some papers and the performance of these approaches is becoming appreciable and is now well understood.In this publication,the author proposes to extend this discretization for full-potential electronic structure calculations by combining the refinement of the finite element mesh,where the solution is most singular with the increase of the degree of the polynomial approximations in the regions where the solution is mostly regular.This combination of increase of approximation properties,done in an a priori or a posteriori manner,is well-known to generally produce an optimal exponential type convergence rate with respect to the number of degrees of freedom even when the solution is singular.The analysis performed here sustains this property in the case of Hartree-Fock and Kohn-Sham problems.