迭代计算

In the first part,two methods calculating the coefficients of nilpotentclass normal forms are proposed.one is the iteration search method based onrepresentation theory of Li-algebra,and another is a new matrixrepresentation method based on the adjoint operator concepts,both are ableto be used to analyse the normal form problems with high orders and largedimensions efficiently.

在第一部分工作中，对于幂零类规范形的系数计算，分别提出了基于李代数表示论的迭代搜索的理论和方法以及基于共轭算子概念的新的矩阵表示的理论和方法，从而有效地解决了维数和阶数较高时的计算问题。

The paper taked 20 nodes isoparametric element as an example and put forward a kind of numerical method combined with the Newton iterative algorithm and Gauss integral algorithm to calculate equivalent loads of prestress in body element.

本文以20节点等参单元为例，提出一种运用高斯积分和牛顿迭代法的数值算法计算实体单元的预应力等代荷载，该方法能够适应各种复杂的预应力钢束形状，并适合计算机编程。

The heating mechanism of chromosphere from coronal soft X-ray radiation, was introduced self-consistently for first time; in numerical technique, we developed an elaborative method to resolve and track the transition region as well as chromospheric condensation.

在计算方法上，提出了增加辐射损失项循环来迭代求解动力学方程组的总体计算方法；并详细阐述了精确分辨和跟踪过渡区的网格调整方法，包括插入、消去和跟踪色球压缩区的方法，并就整个计算实现过程进行了讨论。

The non-structure grid is used for complex irregular boundary processing. An efficient algorithm PISO is used for the model and it can correct the bias of the mesh, so it can reduce iterative times. The flow pattern, energy dissipation ratio and velocity field are obtained.

根据不同的运行工况，利用计算流体力学软件FLUENT对无压隧洞洞内消能工的水流流态进行了二维简化数学模型的数值模拟，在求解过程中采用混合结构网格来处理复杂的边界形状；采用了效率较高PISO算法进行计算，在计算过程中进行了相邻校正和偏斜校正，减少了达到收敛所需的迭代次数。

Our model is obviously superior to Rinker'smodel. because Rinker's model potential is a combination of Thomas-Fermi-Dirac potential and Hartree-Fock-Slater potential for the isolated ion.

我们的模型明显优越于Rinker的模型在于： Rinker的模型采用的是Thomas-Fermi-Dirac势和自由原子的Hartree-Fock-Slater势的迭加形式，而我们的模型中除离子的结构因子外，电子散射势、化学势及电离度等量都是通过自洽迭代方法计算的。

Shim current calculation When shim coils are excited by appropriate current, they can generate correcting magnetic field to compensate the imaging magnetic field unhomogeneity. Based on the indirect calculation method, we proposed a novel iterative optimization algorithm to calculate shim current. Because there is a direct proportion relationship between FID signal and magnetic field homogeneity, we use the intensity of FID signal as feedback information to the calculation. Shim current can be worked out in less than 3 minutes. This satisfied the requirement that active shimming should be performed in real time.

5匀场电流计算对匀场线圈施加适当的电流后才能产生校正磁场消除成像磁场的非均匀分量，本文在匀场电流间接计算方法的基础上，利用磁共振成像原理中磁场均匀性与系统FID信号强度成正比的关系提出了一种电流迭代优化算法，将系统FID信号强度的变化作为反馈信息，能够快速计算出匀场电流对成像磁场进行补偿校正，平均耗时不到三分钟，满足磁共振成像系统对有源匀场的实时性要求。

Shim current calculationWhen shim coils are excited by appropriate current, they can generate correcting magnetic field to compensate the imaging magnetic field unhomogeneity. Based on the indirect calculation method, we proposed a novel iterative optimization algorithm to calculate shim current. Because there is a direct proportion relationship between FID signal and magnetic field homogeneity, we use the intensity of FID signal as feedback information to the calculation. Shim current can be worked out in less than 3 minutes. This satisfied the requirement that active shimming should be performed in real time.

5匀场电流计算对匀场线圈施加适当的电流后才能产生校正磁场消除成像磁场的非均匀分量，本文在匀场电流间接计算方法的基础上，利用磁共振成像原理中磁场均匀性与系统FID信号强度成正比的关系提出了一种电流迭代优化算法，将系统FID信号强度的变化作为反馈信息，能够快速计算出匀场电流对成像磁场进行补偿校正，平均耗时不到三分钟，满足磁共振成像系统对有源匀场的实时性要求。

In this paper, basted on the sum-up and investigation of simulation calculation of long-span bridge construction in nation and international, the detailed approach of imitated calculation of long-span CFST arch bridge is given out, and the reason why the general backward analysis is not suitable for the application of the rib-hoisting of CFST arch bridge is analyzed. And an applied method for forward analysis based on iterative theory is put forward.

本论文通过对国内外桥梁施工仿真计算成果的总结和研究，给出了大跨度钢管混凝土拱桥仿真计算的具体步骤，分析了一般的倒退仿真计算方法不适合应用于钢管混凝土拱桥吊装的原因，并为此提出了基于迭代理论的前进分析实用方法。

3D-CTM (Coupled Thermo-Mechanical Forming Simulation) software for precision forging process of aero-engine blade was developed. The key technologies of 3D coupled rigid-viscoplastic thermo-mechanical FEM simulation of blade forging process were studied systematically. By using the remeshing method of contracting from the boundary to the inner, new mesh system from old distorted mesh system can be obtained. A method of modifying the position of nodes touching on the die according to its original normal was proposed to avoid "dead lock" problem due to uncontinuity of normal of scatted die meshes. The pseudo-static iterative algorithm was used to simplify the coupled thermo-mechanical computation. In particular, formulations to determine relaxation factor β was established for rigid viscoplastic FEM adopting penalty function method, and an improved cubic factor rapid algorithm derived from these formulations was proposed by combining with the advantage of advance and retreat search method.

采用基于边界构形的内缩法，实现了三维畸变网格的重新划分；提出了初矢修正法对触模节点的位置进行修正，解决了由于离散的模具网格的法矢不连续造成的&死锁&问题；采用准静态迭代法简化了速度场和温度场耦合计算过程；特别是针对减速因子β的选取，建立了适用于三维复杂成形过程刚粘塑性罚函数法有限元三次因子法的计算公式，并结合进退搜索法提出了改进的三次因子快速算法，提高了模拟计算效率和稳定性，在此基础之上，开发了面向叶片精锻过程的三维刚粘塑性热力耦合有限元模拟分析系统(3D-CTM)，系统的可靠性得到了圆柱体镦粗的验证。

The modal parameters of some typical structures, such as cantilever beam, stiffened plate were calculated with the iteration method.

用这种迭代算法计算了几种典型阻尼结构悬臂梁和压筋板的模态参数，计算结果与试验模态分析结果或理论解析计算的结果基本一致。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。