查询词典 direction-finding

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 computation of two-dimensional advection transport using current methods such as Alternating Direction Implicit Method and linear interpolation technique can be subject to numerical attenuation,parasite oscillation and poor reproduction of wave propagation when large time steps are used.

在概化的平面区域内，采用上述方法模拟了二维初始浓度高斯分布和水流激波在旋转速度场及均匀速度场上的对流输移问题，结果表明方法在优化幅值衰减和数值扰动以及计算效率方面具有相当的发展潜力和应用前景

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。

To reduce the large numerical dispersion error for the alternating direction implicit finite-difference time-domain method, an isotropic ADI-FDTD method with low numerical dispersion error was presented.

针对交替方向隐式时域有限差分方法数值色散严重的缺点，提出了一种低数值色散的各向同性ADI-FDTD方法。

Based on the second- and fourth-order compact difference formulas for second-order derivatives and the idea of weighted average, two classes of the alternating direction implicit method are proposed for solving two-dimensional wave equation. The methods are of accuracy O (T^2+h^4) and O (T^4+h^4) respectively. Stability conditions are obtained by Fourier analysis method.

基于二阶微商的四阶紧致差商逼近公式及加权平均思想，提出了数值求解二维波动方程的2种精度分别为O(т^2+h^4)和O(т^4+h^4)的交替方向隐式格式，以及与其相匹配的第一个时间层的同阶离散格式，并且通过Foulier方法分析了格式的稳定性。

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。

Basing on the nonatationary linear mild-slope equation developed by Hong Guangwen in 1995, a complete wave model is built considering the bottom friction, nonlinear dispersion relation, and allied reflection and diffraction of several islands. Integrating with corresponding physical and imaginary boundaries, it is solved through Alternating Direction Implicit difference method.

本文以洪广文(1995)推导的非定常线性波缓坡方程为基础，建立考虑底摩阻项，非线性弥散关系，及多岛屿绕射反射作用的缓坡方程求解模式，采用经典的ADI法差分格式，结合物理和虚拟边界条件进行求解。

In the fourth chapter, we build the model of coefficient on one dimension partial differential equation and adopt finite element method to discrete partial differential equation and in the fifth chapter, we employ GP to identify and build the model of right-side function and adopt over-relaxation or alternating direction implicit method to solute difference equation.

在求解这些偏微分方程连续系数反演或右端连一一一~武卫1里鱼立二大一至」夔里匕崖匕位止透二立一一一一续函数的适应值评价中，我们都采用H'一范数正则化来解决连续参数的识别问题。

An extended hyperbolic mild-slope equation, which can take such terms as wind input, bottom friction and nonlinearity of wave into account, here has been deduced into a parabolic one in the form of a series of governing equations described with complex amplitude. It became a complete wave model when integrated with corresponding physical and imaginary boundaries, and can be solved through the improved Crank-Nicholson or the well known Alternating Direction Implicit difference method, both of which can accelerate the convergent speed , expand limitation of the mathematical method and improve the quality of the solution.

本文基于综合考虑底摩阻、风能输入及非线性影响的推广双曲型缓坡方程，将其进行转换，产生一个演变方程，其复振幅控制方程为抛物线性，并采用ADI差分格式、改进的Crank-Nicholson格式及相应的物理和虚拟边界条件进行求解，以提高数值模拟的适用性、数值计算的稳定性、收敛速度及精度。

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。

Breath, muscle contraction of the buttocks; arch body, as far as possible to hold his head, right leg straight towards the ceiling (peg-leg knee in order to avoid muscle tension).

呼气，收缩臀部肌肉；拱起身体，尽量抬起头来，右腿伸直朝向天花板（膝微屈，以避免肌肉紧张）。

The cost of moving grain food products was unchanged from May, but year over year are up 8%.

粮食产品的运输费用与5月份相比没有变化，但却比去年同期高8％。