查询词典 diffusion equation

A numerical calculation program is written up for the various solution methods in this paper and the program is being used in various aspects of inverse problem of environmental hydraulics, including inverse problem in reverse process of one-dimensional unstable diffusion, inverse problem in reverse process of convection-diffusion, inverse problem for the dispersion coefficient in water quality model, The inverse problem of coefficient identification for nonlinear Boussinesq equation, parameter identification inverse problem for water quality model, the inversion of parameter of BOD-DO water model, the inverse problem of the source of convection-diffusion, identification of the steady-state permeability for two dimensional isotropic medium, two-dimensional steady inverse problem of convection-diffusion and parameter identification inverse problem for two-dimensional parabolic equation, etc.

对本文提出的各种算法，编制了数值计算程序，并把它应用于环境水力学反问题诸多领域，包括污染物一维非恒定扩散逆过程反问题，对流扩散方程逆过程反问题，河流水质纵向弥散系数反问题，非线性Boussinesq方程反问题，河流水质多参数识别反问题，BOD-DO水质模型参数反演问题，对流—扩散方程源项反问题及二维恒定各向同性介质渗透系数反问题，二维定常对流——扩散方程及二维抛物型方程参数控制反问题等。

In this paper,two nonlinear anisotropic diffusion filtering methods are presented and they are based on the multispectral anisotropic diffusion models proposed by Pope and Acton.We build a couple of new diffusion coefficients in partial derivative equation based on Tukey's biweight estimator error norm by recurring to the relationship between robust statistics and anisotropic diffusion incorporated with the nonlinear time-dependent cooling technique for gradient threshold.

在Pope和Acton提出的两个多光谱图像各向异性扩散滤波模型的基础上，通过各向异性扩散和稳健统计学的联系，建立了基于B iwe ight Estim ator误差模型的扩散系数，同时利用非线性退化技术对梯度阈值的改进，提出了两个基于各向异性扩散方程的非线性滤波方法。

The microstructure evolution and composition distribution of the 7A55 cast and homogenized alloy were studied by optical microscopy, scanning electron microcopy, energy dispersive spectrometer, transmission electron microscopy and X-ray diffractometry. The homogenizing and overburnt temperatures of the alloy were determined. Meanwhile, the diffusion kinetics of the alloy elements during homogenizing treatment was investigated and the homogenizing kinetic equation was deduced according to Fick's First Law of diffusion. The diffusion of alloy elements, precipitation of Al3Zr particles and the conglomeration and globe of the insoluble phases were explained by the equation during homogenization.

摘 要：采用光学显微镜、扫描电镜、能谱分析、透射电镜和X射线衍射分析等研究了7A55合金铸态与均匀化显微组织演化与成分分布，确定了该合金的均匀化处理温度与过烧温度，研究了铸锭均匀化动力学过程，利用菲克定理导出了均匀化动力学方程，利用动力学方程对均匀化过程中合金元素的扩散、 Al3Zr的析出、难熔相的聚集和球化现象进行了解释。

In this paper, the influential factors on the dual induction log ging response of reservoir with mud filtrate invasion are analyzed on the basis of the filtration theory of oil-water two-phase flow, the diffusion equation and the electrolog theory.

依据油水两相渗流理论、水的对流方程，结合电测井理论，进行泥浆侵入地层的双感应测井响应特性分析。

Based on GIS and water pollution model, the paper discusses sulfured pollution in Yellow River, analyses diffusion equation of sulfured pollution, implements visible presentation, provides a new method for water pollution control and management.

本文以黄河某河段的硫化物污染为例，基于GIS技术和水环境数值模拟方程，研究污染物在水环境中的运移扩散规律，并实现污染物扩散的可视化表达，探索污染控制和治理的新方法。

The diffusion equation describing the light transportation in two dimensional two layers dental model with finite size is solved by finite element method,and the optical intensity distribution inside the dental tissueis is obtained.

利用有限元方法对光在二维牙齿双层有限尺寸模型中传输的扩散方程进行求解，获取了光能在组织体内部的分布情况，并对牙釉质和牙本质在不同光学参量模型下的光学穿透深度进行仿真分析。

Moreover, the complete nine-point scheme for 2D convection-diffusion equation was developed.

在此基础上，提出二维对流扩散方程完全9点格式，可用于任意曲线坐标网格。

In the work, the spin-dependent electrical conductivity and the current spin polarization are self-consistently derived applying the spin drift-diffusion equation on the ferromagnetic/organic structure.

在有机半导体自旋电子器件中，自旋从铁磁极注入到有机半导体后，自旋相上的极化子和自旋向下的极化子有不同的态密度，从而产生不同的电导。

A seven-node difference scheme of the diffusion equation was proposed to study the behaviors of transient electromagnetic field in complicated 3-D geoelectric body. Models of roadway and anomaly body were set up for simulating the transient field excited by a vertical magnetic dipole source. The result of numerical simulation shows that the presence of low resistive conductor leads to noticeable distortion of isolines for the "smoke ring" field, whereas the distortion is not so obvious where the roadway and the poor conductor are located.

为了探讨复杂三维地电体中瞬变电磁场的响应特征，推导了三维扩散方程的七点差分格式，建立了巷道和异常体模型，并对垂直磁偶源激发的瞬变场进行了数值模拟，观察到早期&烟圈&场在低阻体处等值线发生的明显畸变，在巷道和高阻体处的畸变较弱，随着时间的增加异常体的影响逐渐减弱。

Considing the complication of crenellated radial labyrinth geometry, a Taylor-Galerkin finite element scheme is developed to solve the multi-dimensional unsteady viscous convection-diffusion equation.

针对锯齿型迷宫密封几何形状的复杂性，发展了求解多维粘性非定常对流扩散方程的Taylor—Galerkin有限元法。

As she looked at Warrington's manly face, and dark, melancholy eyes, she had settled in her mind that he must have been the victim of an unhappy attachment.

每逢看到沃林顿那刚毅的脸，那乌黑、忧郁的眼睛，她便会相信，他一定作过不幸的爱情的受害者。

Maybe they'll disappear into a pothole.

也许他们将在壶穴里消失