共查询到20条相似文献,搜索用时 109 毫秒
1.
对于高中物理力学中的动态平衡问题,本文总结了几种处理方法,有动态图解法、相似三角形法、正交分解法、整体法和隔离法、正弦定理法、极值法,且指明了每种方法的原理和适用条件。 相似文献
2.
3.
轮廓仪在柱面镜检测中的应用 总被引:1,自引:0,他引:1
目前柱面镜检测的主要方法是样板比较法和干涉法。样板法对球面、柱面样板均有较高要求,而干涉法也需合适的高要求的辅助镜,并且对环境要求较严格。提出了用轮廓仪配用合适工装检测柱面镜的方法,该方法简洁、直观、快速,对环境要求较低。分析了该方法的检测误差,实验验证了分析的正确性,指出高精度轮廓仪在一定范围内能保证柱面镜的检测精度。这种方法不仅适用于零件的最终检测,也适用于加工过程中的检测。 相似文献
4.
5.
介绍了模拟自适应光学系统中受大气湍流影响的光学波前的四种方法,即基于Zernike多项式的K—L函数展开法、小波法、Fourier法以及ARMA法。分析比较了四种方法模拟精度和速度。结果表明,前两种方法不论是精度还是速度上都比较好,更适合湍流波前的模拟。 相似文献
6.
将重构核粒子法(RKPM)和边界积分方程方法结合,提出了一种新的边界积分方程无网格方法——重构核粒子边界无单元法(RKP-BEFM).对弹性力学问题,推导了其重构核粒子边界无单元法的公式,研究其数值积分方案,建立了重构核粒子边界无单元法离散化边界积分方程,并推导了重构核粒子边界无单元法的内点位移和应力积分公式.重构核粒子法形成的形函数具有重构核函数的光滑性,且能再现多项式在插值点的精确值,所以本方法具有更高的精度.最后给出了数值算例,验证了本方法的有效性和正确性.
关键词:
重构核粒子法
弹性力学
边界无单元法 相似文献
7.
8.
9.
在ICP-AES中,卡尔曼滤波是一种有效的光谱干扰校正方法,它在强背景、谱线重叠严重的情况下,仍可得到很好的分析结果;并且有比传统分析线法在纯组分试样条件下更低的检出限。然而,噪声的存在影响了卡尔曼滤波的准确度。小波变换因其多分辨分析的特性,近年来被用于分析信号的去噪,而且该方法简单、快速,是一种很有效的去噪方法。本文首先用仿真数据研究了噪声对卡尔曼滤波法的影响;其次,将小波变换引入卡尔曼滤波法,提出了基于小波变换的卡尔曼滤波法,仿真实验结果表明,该方法能有效提高卡尔曼滤波法的分析准确度。 相似文献
10.
11.
12.
13.
14.
G. Shirkov 《辐射效应与固体损伤》2013,168(10-12):483-493
15.
16.
Transported probability density function (PDF) methods have been applied widely and effectively for modelling turbulent reacting flows. In most applications of PDF methods to date, Lagrangian particle Monte Carlo algorithms have been used to solve a modelled PDF transport equation. However, Lagrangian particle PDF methods are computationally intensive and are not readily integrated into conventional Eulerian computational fluid dynamics (CFD) codes. Eulerian field PDF methods have been proposed as an alternative. Here a systematic comparison is performed among three methods for solving the same underlying modelled composition PDF transport equation: a consistent hybrid Lagrangian particle/Eulerian mesh (LPEM) method, a stochastic Eulerian field (SEF) method and a deterministic Eulerian field method with a direct-quadrature-method-of-moments closure (a multi-environment PDF-MEPDF method). The comparisons have been made in simulations of a series of three non-premixed, piloted methane–air turbulent jet flames that exhibit progressively increasing levels of local extinction and turbulence-chemistry interactions: Sandia/TUD flames D, E and F. The three PDF methods have been implemented using the same underlying CFD solver, and results obtained using the three methods have been compared using (to the extent possible) equivalent physical models and numerical parameters. Reasonably converged mean and rms scalar profiles are obtained using 40 particles per cell for the LPEM method or 40 Eulerian fields for the SEF method. Results from these stochastic methods are compared with results obtained using two- and three-environment MEPDF methods. The relative advantages and disadvantages of each method in terms of accuracy and computational requirements are explored and identified. In general, the results obtained from the two stochastic methods (LPEM and SEF) are very similar, and are in closer agreement with experimental measurements than those obtained using the MEPDF method, while MEPDF is the most computationally efficient of the three methods. These and other findings are discussed in detail. 相似文献
17.
18.
Self-consistent field method and non-self-consistent field method for calculating the positron lifetime 下载免费PDF全文
Many methods are used to calculate the positron lifetime,these methods could be divided into two main types.The first method is atomic superposition approximation method and the second one is the so called energy band calculation method.They are also known as the non-self-consistent field method and self-consistent field method respectively.In this paper,we first introduce the two basic methods and then,we take Si as an example and give our calculation results,these results coincide with our latest experimental results,finally,we discuss the advantages and disadvantages of the two methods. 相似文献
19.