扩散

Chapter 2Finally, molecular dynamics simulations were performed to investigate the effect of catenation on methane diffusion as well as diffusion mechanism in those materials.

第二章我们进一步研究了互穿结构对甲烷扩散的影响以及气体在该类材料中的扩散机理，发现互穿结构导致室温下甲烷的扩散系数被降低了3～5倍，远大于对氢气扩散系数的影响。

The invention also discloses a relative report sender, which comprises inquirer for inquiring said disperse equivalent chain group; a controller for generating sending command to the sender when there is the disperse equivalent chain group; a sender for sending LSA refresh report at the main disperse chain.

本发明还公开了一种报文发送装置，该装置包括：查询单元，用于在网络设备发送LSA更新报文时查询所述网络设备与其邻居设备间的扩散等价链路组信息；控制单元，用于当查询结果为网络设备与其邻居设备间存在扩散等价链路组时，生成发送命令下发给发送单元；发送单元，用于按照所述发送命令，只在所述扩散等价链路组的主扩散链路上向邻居网络设备发送所述LSA更新报文。

The profile distributions of silicate, phosphate and nitrate suggest that the organic material decomposition in area is mainly through nitrification during early diagenesis. Based on benthic fluxes of nutrients calculated using Fick's first law, benthic fluxes of silicate, phosphate and nitrate are -886.45~42.62 mol/(m^2d),-3.04~5.83 mol/(m^2d) and -189.43~21.05 mol-(m^2d), respectively, and perhaps silicate and nitrate are one of the major sources of nutrients for bottom water. Our results also reveal temporal and spatial variations of benthic fluxes for silicate, phosphate and nitrate, which may be related to sedimentation environment changes caused by global climatologic change.

在水－沉积物介面附近矽酸盐、磷酸盐和硝酸盐都存在著极陡的浓度梯度，Fick扩散定理的计算结果表明，研究区内矽酸盐、磷酸盐和硝酸盐的海底扩散通量分别为-886.45～42.62mol/、-3.04～5.83mol/和-189.43～21.05mol/，且矽酸盐和硝酸盐主要是从沉积物向底层水体扩散，是底层水体营养盐的来源之一；研究区内矽酸盐、磷酸盐和硝酸盐的海底扩散通量存在著一定的时间和空间变化，这可能与因全球气候变化而导致的沉积环境的改变有关。

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。

And we show that random walk model converges to the stable law of Lévy-Feller advection-dispersion equation by use of a properly scaled transition to vanish-ing space and time steps,We propose an explicit finite difference approximation for Lévy-Feller advection-dispersion equation.

第三章讨论描述服从某种稳定分布反常扩散的非对称空间分数阶对流-扩散方程——Lévy-Feller对流-扩散方程，首先利用Fourier变换和Laplace变换给出方程的基本解，然后利用Grünwald-Letnikov分数阶导数移位离散算子离散方程中的Riesz-Feller分数阶导数得到离散格式，证明此格式可以解释为离散随机游走模型，并且证明了当时间和空间步长以一定的比率同时趋于0时，所提出的离散随机游走模型收敛到Lévy-Feller对流-扩散过程的稳定分布。

Thus, non-negative property is suggested as the criterion of stability. Further, diffusion coefficient is replaced by an artificial one in the finite difference equation to simulate the entropy generation can improve the accuracy of the numerical analysis.

在尽可能满足对流扩散过程数值格式中的输运性或守恒性及稳定性的同时，以扩散熵产仿真为原则的伪扩散系数可有效地提高数值模拟的仿真性，为数值计算中扩散系数的修正提供了一种有效的手段。

The conclusion shows that gas diffesion model under the third kind boundny conditionincludes the m0del under the first Kind boundary condition;mass transfer Biot criterion can repressent the featoreof gas diffesion field of coal particles.Moreover,the measurement method of gas diffu...

结论表明，第三类边界条件下的瓦斯扩散模型包含以往研究的第一类边界条件下的扩散模型，传质毕欧准数能表征煤粒瓦斯扩散场的特点；介绍了测试煤粒瓦斯扩散系数和表面传质系数的方法，给出了测试实例。

Diffusion problem of a predator-prey model with Holling typeⅡfunctional capturing function is studied. Stability condition is obtained when diffusion is absent, and the effect on stability of positive equilibrium is studied when diffusion is present. In the end, the problem of existence of limit cycle is proved in the first quadrant when diffusion is absent.

针对一类具有HollingⅡ型功能捕获函数的捕食－食饵模型的扩散问题进行了研究，得到了无扩散时正平衡点的稳定条件，以及扩散存在时对正平衡点稳定性产生的影响，最后证明了无扩散时系统在第一象限存在极限环的问题。

The new model adapts an operator like coherence enhancement diffusion for edge orientation, and defines eigenvalues based on edgers orientation such that the new tensor has positive diffusion coefficient in edge direction and negative diffusion coefficient in gradient direction.

采用类似相干增强扩散的边缘定向算子实现对边缘的定向，然后根据边缘定向的结果设置扩散张量的特征根，使扩散张量沿边缘方向为正向扩散以增强边缘，而垂直于边缘方向为逆扩散以锐化边缘。

Scholars both here and abroad widely accept that diffusional environment is one of the most important factors to influence green-technology diffusion. To eliminate or conquer green technology diffusion obstacles so that to promote green-technology's rapid and broad diffusion, most researchers bring forward a series of suggestions of improve diffusional environment.

尽管国内外学者普遍认同扩散环境是影响绿色技术扩散的重要因素，为减轻或克服绿色技术扩散壁垒，达到促进绿色技术快速、大范围扩散的目标，许多研究人员提出一系列改善扩散环境的建议。

On the other hand, the more important thing is because the urban housing is a kind of heterogeneity products.

另一方面，更重要的是由于城市住房是一种异质性产品。

Climate histogram is the fall that collects place measure calm value, cent serves as cross axle for a few equal interval, the area that the frequency that the value appears according to place is accumulated and becomes will be determined inside each interval, discharge the graph that rise with post, also be called histogram.

气候直方图是将所收集的降水量测定值，分为几个相等的区间作为横轴，并将各区间内所测定值依所出现的次数累积而成的面积，用柱子排起来的图形，也叫做柱状图。