查询词典 coefficient of diffusion

The new method is a combination of characteristic approximation to handle the convection part, to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion, a smaller time truncation is gained at the same time, and a mixed finite elementspatial approximation to deal with the diffusion part, the sealer unknown and the adjoint vector function are approximated optimally and simultaneously.

此方法即为对方程的对流项沿流体流动的方向即特征方向进行离散，从而保证格式在流动锋线前沿逼近的高稳定性，消除了数值弥散现象，并得到了较小的时间截断误差；另一方面，对方程的扩散项采用混合元离散，可同时高精度逼近未知函数及其伴随向量函数，理论分析表明，此方法是稳定的，具有最优的L~2逼近精度。

The characteristic approximation is used to handle the convection part along the direc-tion of fluid namely characteristic direction to ensure the high stability of the method in approximating the sharp fronts and reduce the numerical diffusion; The mixed finite element spatial approximation is employed to deal with diffusion part and approximate the scalar unknown and the adjoint vector function optimally and simultaneously; In order to preserve the integral conservation of the method, we introduce the modified characteristic method.

该方法对方程的对流部分沿流体流动的方向即特征方向离散以保证格式在流动的锋线前沿逼近的高稳定性，消除数值弥散现象；对方程的扩散部分采用最低次混合有限元方法离散、同时以高精度逼近未知函数及未知函数的梯度；为保证方法的整体守恒性，在格式中引入修正项。

There exist negative correlations between the ionic porosity, which is a measure of atomic packing density in minerals, and Ar and H diffusion activation energies. Thus ionic porosity can be used to predict element diffusion coefficients.

孔隙度作为矿物内部离子堆积密度的一种量度，它与Ar和H的扩散活化能之间存在负的线性相关性，因而可以用于预测元素在矿物中的扩散系数。

The results showed that laminar diffusion flame heights of NG, CO and H2 were proportional to the fuel fluxes; the exit diameter of Bunsen burner had made little effect on the laminar diffusion flame height.

针对多联产系统中弛放气和粗煤气的基本可燃成分，对单组分天然气、一氧化碳及氢气（H2），以及不同比例配制的双组分和多组分气体的扩散火焰高度，预混火焰高度，火焰传播速度，脱火边界，黄焰边界等燃烧特性进行了试验研究。

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。

Objective: To evaluate the value of apparent diffusion coefficients in Magnetic Resonance diffusion weighted imaging with echo-planar technique in depicting the tumor cellularity and grading of astrocytomas.

目的：运用磁共振弥散加权成像技术评估近似弥散系数在星形细胞瘤的细胞密度和病理分级中的作用。

Gas diffusion layer is one of the most important components in proton exchange membrane fuel cell. The contact resistance between current collector and gas diffusion layer is an important part of the total resistance of fuel cell and is also a key factor led to the power loss of PEMFC.

气体扩散层是质子交换膜燃料电池的重要组件，其与极板之间的接触电阻是燃料电池内阻的重要组成部分，也是导致燃料电池功率损失的重要因素。

Objective:To correlatively study the relationship between the water diffusion parameters measured using diffusion tensor imaging and the histological malignancy of astrocytoma.

目的：探讨扩散张量成像测量水分子扩散状态的参数相对值与星形细胞瘤恶性程度之间的相关性。

So, we make the selective emission through the one step diffusion method by the countercheck effect instead of by the ordinary two step diffusion method.

因此，我们认为可以通过利用SiO_2的阻挡作用，结合机械刻槽和丝网印刷，通过一次扩散宋代替通常的分两次进行扩散宋制作"选择性发射极"的方法。

With the counterflow diffusion flame serving as an object of investigation and by the use of a detailed elementary reaction kinetics model based numerical analysis method a study was conducted of the influence of thermal radiation on the flame structure and NO x formation in a methane/oxygen enriched (oxygen concentration 60%) air diffusion flame.

在富氧燃烧的研究方面，国内已有一些利用富氧燃烧节能降耗的应用性报道，但是，对富氧燃烧的火焰特性以及污染物的排放等方面的基础特性研究还比较少。

Researches reveal that students who suffer from corporal punishment tend to resort to violence in their future life.

研究表明遭受过肉体惩罚的孩子倾向于在他们今后的人生中使用暴力。

Total sugar of sarcocarp and chlorophyll of pericarp increased firstly, and then decreased afterward along with altitude; Titratable acidity, ascorbicacid and anthocyanin of pericarp were increased along with altitude; The content of protein increased firstly and decreased afterward along with altitude; Carotenoid of pericarp were decreased along with altitude.

果肉总糖和果皮叶绿素含量随海拔高度升高先升高后降低；可滴定酸、维生素C和果皮花青苷含量均随海拔升高而升高；蛋白质在1720m处最大，1420m处最小；果皮类胡萝卜素随海拔升高而降低。