查询词典 approximate method

Continuation--Optimization method is proposed for approximate synthesis of linkages The synthesis of planar four-bar and six-bar linkages are studied using this method and several solutions are obtained. Thus, selection of the optimum solution for approximate synthesis of linkages is realized.

提出了机构近似综合的连续---优化法，并应用该方法研究了平面铰链四杆及六杆机构的函数综合，得到了多组机构尺寸方案，实现了机构近似综合的多方案优选。

Fist, comprehensive analysis on the current study on data processing is made, and characters of Newton methods about nonlinear surveying and mapping data processing are discussed, and then new solutions to parameters estimate with multi-sources, multi-types, multi-dimension, multi-precision bynonlinear least square are presented such as PSB algorithm, digital continuation and generalized digital continuation algorithm, cone model method, tensor analysis method, GCMA(mixed algorithm of gradient method and conjugate gradient method), combining algorithm based on Newton method and gradient method and confidence region and so on, and a new fast difference iterative algorithm is proposed towards parameters estimation containing random parameters in nonlinear models, and a new solutions to nonlinear least squares surveying and mapping adjustment by parameters estimation both considering the random and nonrandom parameters is presented after studying on nonlinear data processing in deformation monitoring, and at last primary analysis on error propagation of spatial data is made and approximate error propagation formula and error analysis formula to length and area are proposed.

首先比较全面分析了目前测量数据处理理论的研究现状，讨论了牛顿类方法在处理非线性模型参数估计方面的特点，研究并给出了求解多源、多类型、多维、多精度、非线性最小二乘测量平差参数估计的若干种新方法，这包括PSB算法、数值延拓及其广义数值延拓算法、锥模型法、张量分析法、基于最速下降法和牛顿法的组合算法、基于最速下降

Z2Bn z$e0A0 Meshless method is a new numerical computation method that is developed rapidly in recent years. Without element mesh and based on the dispersed nodes to form approximate interpolative function dynamically, meshless method has distinct difference with traditional finite element method. Meshless method conquers the problems caused by mesh generation, mesh aberration and mesh move. With provides a new effective means to engineering problem, meshless method obtain highly recognition in international compute mechanics domain and engineering field.

6L！y6K1Q6h0k0 无网格方法是近年来迅速发展起来的一类新型数值计算方法，它们不借助单元网格而是基于离散结点动态构造近似插值函数，与传统的有限元方法有着显著的区别，克服了网格生成、网格畸变和网格移动引起的问题并为工程问题提供了一种新的有效分析方法，受到了国际计算力学界和工程界的高度重视。

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, Galerkin method is employed. First, test functions to satisfy natural boundary conditions are selected. Then the approximate analytic formulations of the system frequency are derived. Meanwhile the approximate analytic formulation of the limit velocity is got.

采用直接法，首先选取满足自然边界条件的试函数，而后求出了系统固有频率的近似解析公式，同时也得到了极限流速的近似解析公式。

The WKB approximate method is one of effective approximate methods in the quantum mechanics .

WKB近似方法是量子力学中有效的近似方法之一。

We have also introduced a method of approximate description of three order systems, using a kind of bang-bang control to approximate the extremal control.

同时利用bang-bang控制来近似极端控制的方法，给出了三阶反稳定系统可控区域的近似描述。

So, in this thesis, discussing the interrelated theory and by using finite element method,fixed Supported Square Plates with openings for different location and size of the openings are investigated. The mechanics rule of plates after openings are presented. A comparison is made for the above plates and the plates supported in three sides and the cantilever of plate in approximate boundary conditions. Some approximate results are obtained.

为此，本文论述了钢筋混凝土板的相关理论并用ANSYS软件分析了四边固支开孔板在不同开孔位置和形状、不同开孔面积的情况下内力的改变，获得了内力改变的规律，并和三边固支板、悬挑板在近似的边界条件下的受力倩况进行比较，得到一些相近的结果。

The dissecting of samples in group2 were difficult. The root of pulmonary artery and ascending aorta failed to be unfolded because fibrous tissue was tough, right and left fibrous trigone were too firm to be solved by hand. Cardiac muscle fibers couldn't be stripped along myofibrillar trajectory since they were prone to break because of their friability.

组2的心脏解剖困难，表现为纤维组织坚韧，游离肺动脉非常困难；徒手无法松解左、右纤维三角，肺动脉和主动脉根部的游离非常困难；心肌纤维坚硬、质脆，解剖时容易断离成碎块，无法沿纤维走行方向剥离。

We have battled against the odds in a province that has become increasingly violent.

我们对在一个争夺日益激烈省的可能性。