扩散

And then, the direct boundary integral equation of convection-diffusion was obtained by using inverse transformation, which is a discrete by using constant elements.

然后，通过逆变换推导出对流扩散方程的直接边界积分方程和解的积分表达式，并采用常单元来离散边界积分方程，完成对流扩散方程的求解。

Compound model because the city develops the sex of in proper sequence later to diffuse with bouncing type centrally,urban district is, make a lot of mix irrelevantly originally the city with very few connection is an organic whole repeatedly gradually, formation urban district.

复合型城市区域是由于城市集中发展之后的循序性扩散与跳跃式扩散，使许多原本不相干的和联系很少的城市逐渐连为一体，形成的城市区域。

objective to obtain the diffusion tensor maps of the normal human brain,and assess intrinstic properties of water diffusion in quantitative parameters for an anatomic analysis.methods maps of isotropic apparent diffusion coefficient and various anisotropic maps were calculated in60healthy adults from seven diffusion imagings by using single-shot echo-planar diffusion-weighted sequence.brain parenchyma anatomy was analyzed and adciso and various anisotropic index were measured.results （1）diffusion properties of different tissues and anatomic areas of normal adult human brain are different.diffusion in white matter is anisotropic;diffusion in gray matter is isotropic.

目的 获取正常人脑组织扩散张力性图像（diffusion densor imaging，dti），定量分析正常人脑组织水扩散的内在特性，进一步评价脑解剖结构。方法 60例健康正常人，应用单次激发epi-dw序列，计算出adciso图及各向异性图，分析脑实质不同区域的解剖结构，测量adciso（isotropic apparent diffusion coefficient）及各向异性指数。结果（1）脑内不同组织结构弥散特性不同，脑白质弥散表现为各向异性，而脑灰质弥散表现为各向同性。

The forward finite difference and Newton iterance are used in the light of box model and other heavy gas dispersion models, such as IIT Heavy Gas Models and virtual point source model, to solve the differential equations of controlling heavy gas cl.

文中从控制重气云团扩散行为的微分方程入手，根据箱模型及其他一些重气扩散模型，如IITHeavyGasModels模型和虚点源模型，采用向前插分和牛顿迭代的方法，针对ThorneyIslandTrialNo 。0 0 8试验进行了数值模拟，得到了重气云团外形尺寸和空气卷吸量随时间的变化关系以及下风向固定点处地面最大浓度值。

The mathematical model of Continuous Annular Chromatgraphy , considering axial and annular dispersion, is established, and the analytical solution is obtained by Laplace integral transforms.

建立了考虑轴向扩散和圆周方向扩散的连续环状色谱分离过程的数学模型，并通过拉普拉斯变换法获得了解析解。

Active sites of a certain concentration are distributed randomly over inactive sites, forming the model of two- dimensional lattice of active sites distribution. Diffusion, especially directional diffusion, of the adsorbed particles is taken into account on the basis of ZGB model.

模型假设，一定浓度的活性位随机分布在非活性位上，形成了活性位分布的二维格子模型反应器，并在ZGB模型的基础上，考虑了氧原子和CO分子的表面扩散，特别是引进了吸附粒子的定向表面扩散。

In 2002, Kou proposed double exponential jump diffusion model, the most important is that double exponential jump diffusion model can generates a highly skewed and leptokurtic distribution, in addition, DEJD leads to tractable analysis pricing formulas for European and path-dependent options.

在2002年，Kou提出了双指数跳扩散模型，该模型最主要的特点就是能产生一个尖峰厚尾分布，更重要的是在双指数跳扩散模型下能给出易处理的欧式期权和奇异期权的解析定价公式。

This is 1 the firstsharp uniform convergence result for linear transport equations in di?usive regime, aproblem that involves both transport and di?usive scales; and 2 the first uniform con-vergence valid up to the boundary even if the boundary layers exist.

这是对线性输运方程已知的第一个在扩散域中和输运扩散同时存在时具有高阶一致收敛性的算法，同时也是第一个一致收敛性在边界层也成立的算法。

In chemical plant,liquefacient ammonia leaking from refrigeration equipment usually disperse in the air and become dense gas at the beginning.With the air coming into the gas,it will be increasingly close to the air density and become non-dense gas.

化工厂制冷装置发生液氨泄漏，泄漏后形成毒气云团在空气中扩散，初期多形成重气云团，在扩散过程中随着空气的不断卷吸，重气云的密度会越来越接近空气，从而转变为非重气云团。

The diffusion coefficient of lith...

锂盐的扩散系数由对称电池的限制扩散法测得，结果为4.8×10-7cm2·S-1。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。