查询词典 diffusion

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。

The thickness of aqueous diffusion layer d(subscript a and diffusion coefficient (d0) of Hg through SLM were evaluated by the linear slope method, and they were found to be 1.57×10^(-5) m and 7.26×10^(-13) m^2/s, respectively.

Hg在N503-煤油支撑液膜体系中的扩散层厚度δa为1.57×10^(-5)m，膜内扩散系数d0为7.26×10^(-13)平方公尺/s，确立了Hg的渗透系数P方程。

The concentration of D-phenylalanine in the external phase and the separation factorαcan be expressed as: The diffusion of boundary layer in outer aqueous phase is the controlled process while the concentration of D-phenylalanine in the external phase far less than the concentration of chiral carrier in the emulsion liquid membrane phase, then the diffusion coefficient k_e of boundary layer in outer aqueous phase can be achieved by data fitting.

外水相苯丙氨酸对映体的浓度以及分离因子α表示为：当外相对映体浓度远小于液膜相手性载体浓度时，该手性传质过程中外相边界层的扩散为控制步骤，利用数据拟合得到了外水相与液膜相界面边界层扩散的传质系数k_e。

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。

PartⅡDiffusion-weighted MR Imaging of breast mass and non-mass lesionPurpose:To evaluate Diffusion-weighted MR Imaging of breast mass and non-mass lesion in lesion characterization by comparing ADCs of malignanty with benignancy.

第二部分磁共振扩散加权成像在乳腺肿块性病变和非肿块性病变中应用价值的对比研究目的：对比乳腺良、恶性病变的表观弥散系数(apparent diffusioncoefficient，ADC)，探讨DWI在乳腺肿块性病变和非肿块性病变中的诊断价值。

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。

Methods Diffusion anisotropy was classified with a method based on apparent diffusion coefficient and spherical harmonic function.

提出了一种基于表观扩散系数和球谐函数的多纤维扩散各向异性分析方法对扩散各向异性进行分类。

Objective To investigate the characteristics of fractional anisotropy and apparent diffusion coefficient of association fiber tracts in patients with amnestic mild cognitive impairment, and to assess the application value of diffusion tensor imaging in differential diagnosis of aMCI and AD.

目的 通过磁共振扩散张量成像探讨遗忘型轻度认知障碍患者联合纤维束FA值和ADC值的变化特点，评价DTI对aMCI的诊断及aMCI与AD鉴别诊断的应用价值。

Do not gum up the work by telling mother what we are going to do .

别告诉母亲我们要干的事，那会把事情搞糟的。

In recent years, application of the partial prestressed concrete beam s is developed.

近年来，随着部分预应力砼梁应用的推广，发现我国规范所采用的名义拉应力法的计算结果不稳定。