交替方向法

In the light of the complex, high-level and non-linear feature of the mathematical model which describe the transport of the coalbed methane, this paper study the fully-implicit solving method of the mathematical model in detail. Based on the complexity of the algebraic equations which are formed eventually, according to the alternating direction implicit difference pattern, this paper use the iterative method and the fully main element Gauss-Jordan eliminating method to solve equations, which is to use the iterative method to determine coefficient matrix and use the fully main element Gauss-Jordan method to solve th linear algebraic equation group, at the same time of studying the solving method of the mathematical model, according to the devising requirement of FORTRAN77 program structure, this paper draw up computer program and form the corresponding computer model, and verify the validity and reliability of the model in theory by operating the model.

重点研究了模型内、外边界及有关参数的处理，针对描述煤层甲烷运移的数学模型是一个复杂、高阶非线性数学模型的特点，详细研究了模型的全隐式求解方法，根据最后形成的代数方程组的复杂性，按交替方向隐式差分格式，采用迭代与全选主元高斯约当消去法相结合的方法求解方程：即确定系数矩阵采用迭代法，求解线性方程组时采用全选主元高斯约当消去法，在研究模型解法的同时按FORTRAN结构化程序设计的要求，编制计算机程序，形成相应的CBMRS计算机模型，并通过模型的运行从理论上证明了模型的正确性与可靠性。

This paper discusses the different differential methods of Alternating Direction Implicit Method with initial condition and boundary conditions in detail.

文摘：详细地研究了各种情形的求解二维抛物型方程初边值问题的交替方向隐式差分法。

Advanced numerical simulations were introduced in soil water research,such as finite analysis method,characteristic finite element method,and alternating direction finite element method.

土壤水研究的数值模拟方法也有一些突破，如有限解析法、特征有限元法、交替方向有限元法等。

The alternating direction implicit method is used to solve discretization equation and supplement block iteration method to quickening convergence.

本文选择交替方向隐式迭代法，并补以块修正技术以促进收敛。

A numerical simulation technique based on the stable alternating direction implicit method and the upper bound element technique is presented and applied to simulations of extrusion directly following liquid infiltration which involves infiltration,solidification, and large plastic deformation in one process.

采用稳定的交替方向隐式有限差分方法、上限元法等数值计算方法模拟了融浸渗、凝固和大塑性变形为一体的液态浸渗后直接挤压的工艺过程。

The technique of boundary-fitted coordinate system is used to overcome the difficulties resulting from the complicated shapes of natural river boundaries;the method of alternating direction implicit finite difference scheme is used to solve the partial differential equations in the transformed plane;and the technique of moving boundary is used to deal with the river bed exposed to water surface.

用适体坐标技术克服天然河道复杂的几何边界给有限差分法所带来的困难；用交替方向隐式有限差分格式求解变换平面上的偏微分方程；用动边界技术处理河床的淹露。

Based on wave propagation feature, this paper analyses 3D seismic migration algorithms such as alternating direction implicit method, LU decomposition method, and inverse operator approach method. The result shows that the alternating direction implicit method is fast but causes distortion in wave field extrapolation and affects image accuracy; however LU decomposition and inverse operator approach methods are fast while holding circular symmetry of wave field, and are promising in oilfield exploration and development.

在波的传播特征分析基础上，对交替方向隐式法、LU分解法、逆算子逼近法等三维地震偏移算法进行了分析研究，结果表明，交替方向隐式法虽然快捷但是在波场外推中明显产生畸变并影响成像的准确性，而LU分解和逆算子逼近法是保持波场圆对称特征前提下的快速算法，在油田勘探开发中具有较好的应用前景。

This thesis contributed to the comprehensive study of the Finite-Difference Time-Domain method and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies. The work includes mainly three parts: the study on the performance of PML absorbing boundary condition applied to pseudo low frequency electromagnetic problems; the validation of the FDTD method with PML absorbing boundary conditions and the corresponding computer software based on the numerical study of the electromagnetic field of an electric dipole antenna, and its application to the numerical computation of radiated electromagnetic fields in switched mode power supplies; the development of an improved alternating direction implicit finite-difference time-domain method.

在综合前人工作基础上，本文对时域有限差分法及其在开关电源辐射电磁场数值计算中的应用进行了系统的分析和研究，其核心内容包括：伪低频电磁场数值计算中PML吸收边界条件性能的研究；基于基准问题—电偶极子天线三维辐射电磁场，验证了本文构造的基于PML吸收边界条件的三维FDTD法及其计算软件，并应用于高频开关电源辐射电磁场的数值分析；提出了一种改进的交替方向隐格式时域有限差分法。

State Key Laboratory of Millimeter Waves, Southeast University , Nanjing 210096, ChinaIn this paper, it is proven that the divergence relationship of electric-field and magnetic-field is non-zero even in charge-free regions, when the electric-field and magnetic-field are calculated with Alternating Direction Implicit Finite-Difference Time-Domain method, and the concrete expression of the divergence relationship is derived.

摘要该文证明了即使在无源区域，交替方向隐式时域有限差分法所给出的电磁场量不满足零散度关系，同时推导出了该散度关系的具体表达式。

This study uses the height function to track the free surface, and the body-fitted coordinate system is used to generate a coordinate surface coindent with the boundary contours in the physical plate.

为求解本研究的流动现象，除了以高度函数法追踪液面外，并以物体嵌合座标系统克服翼形的不规则形状，同时采用SIMPLE数值法来处理整个数值运算过程，并配合交替方向隐式A.D.I。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。