查询词典 multistep method

Firstly, this paper investigated roundly the basic theory of the ambient vibration method, analyzed systematically the main methods of ambient vibration identification, and discussed their advantages and disadvantages. Then we established the finite element model of structural dynamics and test model and analyzed their mutual relation, improved MUSIC method and correlation function method in the harmonic identification, and gave the subspace method and correlation function method based on continuous model, which is multi-harmonic retrieve technique. And then, this paper also puts forward least-squares method to estimate directly structural physical and modal parameters; this approach replaced the derivative operator in the continuous time model with an equivalent approximation, and estimated the physical parameters of structures by the least-squares method. And then, we discussed the approximation methods of derivative and their convergence. Finally, this paper researched the modal parameters of a frame structure by the simulation and test. The results demonstrated that subspace method, correlation function method and the least-squares method are effective and stable respectively.

全面地研究环境振动识别方法的基本理论，系统地分析环境振动识别方法的主要方法，讨论它们的优点和不足；建立结(来源：6666AB44C论文网www.abclunwen.com)构动力学的有限元模型和试验模型，分析有限元模型与试验模型之间的相互关系；改进谐波识别中的MUSIC识别方法和相关函数识别方法，给出大型结构模态识别的连续型的子空间分解识别方法和相关函数识别方法，这个方法是多元谐波识别方法；提出直接识别结构的物理参数和模态参数的最小二乘方法，这个方法利用导数的近似值代替导数值，并运用最小二乘方法识别结构的物理参数，讨论导数近似值的选择方法，分析算法的收敛性；通过仿真计算和模型实验，研究高层框架结构的模态参数识别，验证子空间分解识别方法、相关函数识别方法和最小二乘识别方法的有效性，算法的稳定性；从理论和试验两个方面分析和研究噪声对识别精度的影响，影响识别精度的因素，以及部分模态成分的模态参数不能够被识别的原因。

The revised Hargraves formula has the best result compared with Penman-Monteith formula, the average relative error is 6%, moreover, Hargaves method requiring the least data in calculating ETo, so this method has the high actual application value; The following are Radiation method and Blaney-Criddle method ; The worst is the Pan method, even after revised, the highest and average relative error is 36% and 10%, respectively. So, in this study, Penman-Monteith method, Radiation method, Blaney-Criddle method and Hargraves method are used except Pan method.

在这四种方法中，修正后的Hargraves方法与彭曼—蒙特斯方法的计算结果符合最好，其平均相对误差为6％，而Hargraves方法需要的气象数据只有计算时段的最高、最低温度，该方法具有较高的实际应用价值；辐射方法和布兰尼—克里德尔方法次之；蒸发皿方法最差，即使在修正后，E601型蒸发皿的最大误差也高达36％，平均为10％，所以在预报系统的研究设计中采用了除蒸发皿方法之外的四种方法。

The primary studying works and characteristics:1 To summarize reinforcing theory of cement mixing pile composite foundation2 To analyze the primary mechanics characters and changing rules of cement mixing pile, based on analysis of test data both indoor and outdoor.3 To discuss siding frictional resistance, ending resistance, ultimate bearing capacity of simple mixing pile and effectiveness factor of grouped piles, loading ratio of soil between piles under cushion cap of grouped piles and stress ratio of pile and soil and so on, and use many computation method and experimentation method to ensure bearing capacity of mixing piles composite foundation.4 To point out and analyze eight sides flaws and problems of the bearing capacity calculation method of mixing pile compositefoundation which ensured by national and normative method/ formula.5 To apply test results of loading tests and a few settlement observation data, use gray theory to predicate ultimate bearing capacity of deep mixing piles, actual example demonstrate engaging between theoretical predicted value and actual value.6 To apply groovy layerwise summation method to discuss entity piles method, double foundation method, equivalent layerwise summation method and consolidation theoretical method and so on, especially by combination of engineering example, use FEM to calculate or discuss the settlement and changing rules of composite foundation.7 To discuss problems of critical length of composite foundation by combination of engineering example and numerical analysis method, and analyze the contrast of critical length between simple pile load and most area load of composite foundation, not only critical length of composite foundation is relative to modulus ratio between piles and soil, but also upside load distribution area of composite foundation.

主要的研究工作与特色为：(1)总结了水泥搅拌桩复合地基的加固原理；(2)在对室内外试验资料进行统计分析的基础上，系统分析了搅拌桩水泥土的主要力学特性及其变化规律；(3)探讨了搅拌单桩的侧摩阻力、端阻力、极限承载力及群桩效率系数、群桩承台下桩间土荷载分担比及桩土应力比等，提出用多种计算方法并结合试验方法来综合确定搅拌桩复合地基的承载力；(4)明确指出和分析了按国家有关规范的方法确定搅拌桩复合地基承载力所存在的八个方面的缺陷与问题；(5)利用过去没有加载至破坏阶段的载荷试验成果和较少的沉降观测数据，尝试了用灰色理论预测深层搅拌桩的极限承载力，实例表明理论预测值与实测值吻合较好；(6)在常规分层总和法的基础上，探讨了复合地基沉降计算的实体墩基法、双层地基法、等效作用分层总和法、固结理论法等，特别是结合工程实例，用有限元数值计算等方法计算和讨论了搅拌桩复合地基的沉降及其变化规律；(7)结合工程实例，用数值分析方法探讨了复合地基临界桩长的问题，指出和分析了单桩荷载下的临界桩长与复合地基大面积荷载下的临界桩长存在很大的差别，复合地基的临界桩长不仅与桩土模量比有关，而且与复合地基上部荷载分布面积有关。

In this paper, a kind of designing method about the dashing style, multistep atomizing atomizer is put forward based on the experimental study.

本文在实验研究的基础上对撞击式多级雾化喷嘴提出了一种设计计算方法。

Furthermore, it is proved that, under the sufficient condition, the multistep Runge-Kutta method is GP d-stable if and only if it is A-stable.

在文献 [2 ]中，Bellen等考虑了中立型延迟微分方程解析解及单步Runge -Kutta方法的渐近稳定性。

This paper is devoted to the application of the parallel multistep hybrid method to the numerical solution for a class of Index-2 differential algebraic equations ,and the errors are estimated,it has obtained the extremely ideal result.

将并行多值混合方法应用于一类2-指标微分代数方程的数值处理，并进行误差估计，获得了十分理想的结果。

The properties of the general linear multistep method for piecewise smooth dynamics of mechanical systems are analyzed and a picewise smooth vibration model is introduced. Some numerical experiments on the vibration model are made and several improved integration methods are presented.

采用Taylor级数展开方法，分析了常用的线性多步法在非光滑机械动力系统中的计算精度特性，建立了一个非光滑的机械振动系统检验模型，给出了典型的计算实例，并提出了几种改善计算精度的措施。

In both the cases we provide necessary conditions for any linear multistep method applied to delay differential equations and neutral delay differential equations to be τ(0)-stable and Nτ(0)-stable respectively.

针对这两种情况，分别给出了线性多步方法关于延迟微分方程τ（0）-稳定及中立型延迟微分方程Nτ（0）-稳定的必要条件。

The GP d-stability of the multistep Runge-Kutta method for neutral delay differential equations with different delay terms is investigated.

在文献 [1 ]中，Iserles详细论述了这类方程在生物学、金融学、计算机辅助设计、非线性动力系统等许多科学与工程领域的广泛应用。

The generalized Douglas scheme for variable coefficients is applied to wide-angle multistep finite-difference beam propagation method.

交叉波导是集成光学中一种重要的器件单元，它的应用包括制作能量分配器、光开关[1] 、低损耗低串音的交叉光路网络等。

Finally it offers the analysis of the fault-tolerance system as well as its test verification.

这样，运行于空间环境中的系统的设计目标就是在保证系统实时性

However, it is still difficult to find out the real reason of the increase of the keratinized gingiva during the orthodontic extrusion whether it is due to the proliferation of the gingival tissue or to its elastic nature, that is because the proliferation of the fibroblasts as well as the connective tissue changes in volume and the intra-fibers spaces were all immeasurable in most of the studies.

然而，仍然难以找到真正的原因增加的角化牙龈在正畸挤压它是否是由于扩散的牙龈组织或其弹性性质，这是因为增殖的成纤维细胞以及作为结缔组织的变化量和内部纤维空格都是不可估量的，大多数的研究。