查询词典 diffusion equation

The authors investigated the singular limits of stiff relaxation and dominant diffusion for general 2×2nonlinear systems of balance laws, that is,τ=o,ε→ 0, the relaxation time τtends to zero faster than the diffusion parameter ε. If there exists a priori L∞ bound that is uniformly with respect to ε for the solutionsof a system, then the solution sequence converges to the corresponding equilibrium solution of the system.

研究一般扩散占优的2×2双曲平衡律系统奇异松弛极限，用补偿紧性方法，在松弛时间τ比扩散系数ε趋于零快时，即τ=o，ε→ 0时，得到其解的整体存在性一般框架：如果上述系统的解存在对ε一致的先验L∞估计，则其解序列收敛于上述系统的对应平衡状态解。

However, in parallelism with the accruement, when the factor of effort of knowledge diffusion by the managers in corporation is considered, the model cannot explain the knowledge diffusion rule.

分析了徐渝的知识传播模型，指出该模型阐述的规律适用于知识在企业中自然增长的状况，而考虑企业对知识传播的努力因素时该模型就不再适用。

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。

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。

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。

Sodium citrate; calcium carbonate; calcium hydroxide; potassium bicorbonate; magnesium carbonate; ferrous sulphate; Zinc sulphate; copper sulphate; manganese sulphate; potassium iodide; sodium selenite.

柠檬酸钠；碳酸钙；氢氧化钙；碳酸氢钾；碳酸镁；硫酸亚铁；硫酸锌；硫酸铜；硫酸锰；碘化钾；亚硒酸钠。

All this to say that I'm glad filmmaking hasn't become completely ironic. I can enjoy an ironic film as much as the next person, but they usually involve a message of some sort. One that's delivered in a smirkingly clever way that requires little in the way of talent.

所有这些都是说，我很高兴电影制作没有变成完全讽刺艺术，我可以和下一个人一样享受讽刺电影的乐趣，虽然他们经常会被划归到一定级别，技术方面不需要很高的才能。