问题分析法

Illustrations are used to analyze the limitation of line sampling firstly. For linear limit state, the efficiency of LS is affected by the dispersion of the actual important direction from the optimal one, the bigger the dispersion is, the lower the efficiency is. For non-linear limit state, in case that the actual important direction deviates from the optimal one greatly, the efficiency and the precision of LS decrease seriously, even wrong results are obtained.

首先通过算例分析线抽样方法存在的问题，对于线性问题，线抽样法的效率受抽样重要方向与最优重要方向偏离程度的影响，这种偏离程度越大，效率越低；而对于非线性问题，当抽样重要方向与最优重要方向偏离较大时，线抽样的效率和精度均严重下降，甚至得出错误的计算结果。

The influence of some rnodified genetic algorithms on searchspeed is also examined. Some genetic operations suitable to the optimization technique areobtained, therefore, a novel way of solving a class of optimizations of functions that cannot be realized using the method of steepest descent is proposed.

文中还分析了一些改进的遗传算法对于该问题搜索速度的影响，得到了适于解决此问题的合理的遗传操作，从而为有效地解决最速下降法所不能实现的某一类函数代化问题提供了一种新的途径。

The interpolate algorithms of three-order NURBS curve and double three-orders NURBS surface are presented. The expressions of partial derivative and normal curvature of NURBS surface are derived by the theory of differential geometry. The geometric characteristics of different curvature area of the free-form surfaces are analyzed in detail. All these work lays a theoretical foundation for constructing the cutter location calculating model of free-form surfaces NC machining. 2 On the basis of analyzing the methods of cutter path generation, the standard of evaluating the various methods of cutter path generation is presented. The method of generating cutter path with constant scallop height is presented for the first time.

本文以提高复杂曲面多坐标数控加工精度和加工效率为目的，在对国内外研究现状进行深入分析的基础上，对数控编程中各环节的关键技术问题进行了深入研究，主要内容包括以下几方面： 1 分析了复杂曲面各种造型方法的优缺点，给出了根据各种边界条件所确定自由曲面的NURBS表示方法以及三次NURBS曲线曲面反算算法；用微分几何理论推导了NURBS曲面的偏导矢及法曲率计算表达式；对曲面不同曲率特性区域的几何特征进行了深入分析，为建立复杂曲面的数控加工刀位计算模型奠定了理论基础。

As an effective method of numerical computation, FEM is widely applied in numerical simulation of metal deformation process.

有限元法作为一种有效的数值计算方法已经被广泛应用于金属成形过程的数值模拟方面，但是有限元分析软件在使用过程中也存在许多问题，例如数值模拟解的精度问题，直接优化设计技术参数的问题。

The measurement system error model analysis is introduced into power system real time network state analysis as an important part for the first time, which can improve on the state estimation quality and provide the capability to monitor the operation of the measurement system; 2. The theory and algorithm of the on-line estimation and update of measurement noise variance based on the relation between the residual variance and noise variance. The statistic properties of the sample variance are discussed and the relation between the estimation precision and sample size under given confidence level is derived; 3. The theory and algorithm of detection and identification of measurement bias are presented, which is based on the relation between residual mean and noise mean. The statistic properties of sample mean are discussed and the relation between estimation precision and sample size is derived; 4. The Givens orthogonal transformation algorithm is selected to be the essential algorithm of state estimation, the fast orthogonal transformation algorithm with damp factor and the algorithm which can handle the zero injection measurements efficiently are presented; 5. The quantity analysis theory of bad data detectivity and identifibility are presented, which describes the relation between the elements in matrix W〓 and bad data amplitude and can provide the theory base for measurement system design and valuation.

一、首次将量测系统误差模型分析做为一个环节引入电力系统实时网络状态分析中，为EMS系统增加了实时监视系统运行、修正量测系统误差模型的新功能，进一步发挥了实时网络状态分析应用软件的潜力；二、首次提出了应用样本方差在线估计与修正量测系统误差方差的基本理论，讨论了样本方差的统计性质和概率分布，推导出了样本容量、估计精度和置信度之间的关系，给出了在线估计与修正量测系统误差方差的算法；三、首次提出了应用样本均值在线检测与辨识量测偏差的基本理论，讨论了样本均值的统计性质，推导了样本容量、估计精度和置信度之间的基本关系，给出了在线检测与辨识量测偏差的算法；四、在状态估计算法设计中，以Givens变换算法做为基本算法，提出了快速正交变换阻尼因子法和可以有效地处理零注入量测的混合法，并对实时应用中的一些问题进行了讨论；五、提出了不良数据可检测性与可辨识性的定量分析理论，揭示了描述量测系统配置、网络结构与参数的残差灵敏度矩阵中的元素与不良数据的幅值在可检测、可辨识能力上的定量关系，为量测系统配置设计与评价提供了理论基础；六、综合国内外最新研究成果，采用自适应自回归预测技术和稀疏矢量技术，构造了较完善的不良数据检测与辨识算法。

The classifications, characteristics and recent applications of sliding construction are summarized. Some key technologies of sliding construction such as calculation of sliding drift load, sliding nonsynchronous affection, sliding dynamic response, stability of sliding blocks, and affection on structural mechanics for different sliding blocking have been researched, and the corresponding programs have been coded.

总结了滑移法施工的分类、特点以及应用情况，对于滑移法施工牵引力的计算、滑移不同步影响、滑移法施工激振影响、滑移施工过程中的单元分块稳定性研究、滑移分块对结构成型影响等关键问题进行了理论推导与算例分析，并编制了相关的实用程序。

A analysis on the actualities and a certain problems dealing with headstream, sanitary fill, cremating process and composting process in treatment and disposal of urban refuse in China is conducted.

分析了中国城市生活垃圾处理处置中源头分类、填埋法、焚烧法和堆肥法的现状和存在的问题。

Aiming at the problems occurred in the analytical process of determining the total phosphorus in industrial circulating cooling water by ammonium molybdate spectrophotometry and based on the experience summary,the original analytical method has been improved.

针对用钼酸铵分光光度法测定循环冷却水中的总磷在实际分析过程中遇到的一些问题，经过总结经验，改进了原有的分析方法，降低了测定中的干扰因素，提高了一次分析结果的准确可靠性，使分析结果更为准确可靠。

In this dissertation, first, based on theory of cutting tooth about the gleason spiral bevel gear, the equation of meshing in the process of cutting tooth, the surface equation of generating gear as well as the general tooth surface equation of the double circular arc spiral bevel gear, using GB12759-1991 type of double circular arc gear as a basic gear profile, a three-dimension solid model of double circular arc spiral bevel gear which has the good adaptability was carried out by used of Unigraphics software;Second, by researching of the algorithm about contact and collision as well as various contact types based upon Contacting Finite Element Method, a foundation was laid for selecting the contact type in analyzing contact stress of double circular arc spiral bevel gearing;Finally, through the connection port of PARASOLID between UG software and ANSYS/LS-DYNA software, the three-dimension solid model of double circular arc spiral bevel gearing obtained above in UG was imported into ANSYS/LS-DYNA, a finite element analyzing about contact stress of double circular arc spiral bevel gearing was carried out by applying new loading method.

本文首先基于格利森弧齿锥齿轮加工原理及切齿啮合过程中的啮合方程、产形轮齿面方程以及双圆弧弧齿锥齿轮的齿面方程，选用GB12759-1991型双圆弧齿轮基本齿廓为基准齿形，利用Unigraphics软件的建模功能，绘制了有较好适应性的双圆弧弧齿锥齿轮传动三维实体模型。其次，描述了应用有限单元法进行实体接触与碰撞问题算法的公式，研究了有限元分析中的各种接触类型以及双圆弧弧齿锥齿轮接触应力分析中所选择接触类型的依据。最后，通过UG软件和ANSYS/LS-DYNA之间的PARASOLID接口工具包，将UG软件中得到的啮合齿轮模型导入ANSYS/LS-DYNA有限元分析软件，给出一种新的加载方法，进行了双圆弧弧齿锥齿轮传动的接触应力的有限元分析。

The method of finite element discrete and optimal parameter back analysis is adopted.(3) Concentrated on the question of high external water pressure of the deep-lying tunnel, the basic theory and method calculating external water pressure are systematically studied.(4) Based on Jinping cascade 2 hydropower station, numerical simulation rain infiltration of seepage field under different drainage pattern and grouting pattern are studied, also, the high external water pressure is analyzed and studied and some seepage control measures are put forward.

2采用有限元离散—优化法进行参数的反演分析；(3)针对深埋隧洞的高外水压力问题，进一步分析和研究了衬砌水荷载及外水压力的作用机理和计算方法；(4)以锦屏二级水电站深埋长引水隧洞作为本文的主要研究对象，采用考虑降雨入渗渗流场分析的方法对排水方案和灌浆封堵方案不同情况下的渗流场的水头分布进行了数值模拟，并对其外水压力进行了分析和研究，提出了渗流控制的具体措施。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。