查询词典 diffusion

Thereafter B-A1 paste-layer diffusion technology and close-tube Ga-diffusion technology had been developed, while the former can lead to relatively large the base-region deviation and abruptly varied region in Si, which caused severe decentralization of current amplification parameter β, bad thermal stability and high tr; the latter needed the relatively difficult pack technique, with poor repeatability , high rejection ratio, and poor diffusion quality and production efficiency.

此工艺发明以来，克服了上述两者的弊端，杂质浓度和结深能准确控制而又能任意调整，可进行低、高浓度阶段性掺杂，得到元素Ga在Si中的理想分布，而且表面浓度均匀一致、重复性好、合格率和优品率高，改善和提高了器件的综合性能。

Bonded joint was obtained by diffusion bonding at constant temperature and pressure, phase transformation superplastic diffusion bonding and diffusion bonding under pulsatile pressure. The strength of welding joint was tested and metallography of welding joint was observed.

采用恒温恒压扩散焊、相变超塑性扩散焊和脉冲加压扩散焊实现了钛合金和不锈钢的焊接，测试了焊接接头的强度，并对接头进行了金相观察。

Based on the point that directed diffusion equation is a diffusion process with direction, the correlation between directed diffusion and wavelet transform is studied in this paper.

摘要方向扩散方程是一种有方向性的扩散，本文基于这一特点，对方向扩散方程与小波分解和重构的相关性作了研究。

Initial boundary value problem of two dimensional unsteady diffusion equations is solved in this paper. By using time-dependent fundamental solution of two dimensional diffusion equations and the extension of double layer potential, we establish virtual boundary integral expression of diffusion equations. Then virtual boundary element method is used to implement the numerical computation.

本文在求解二维非定常扩散方程的初边值问题时，利用二维扩散方程与时间有关的基本解，基于双层位势的延拓，建立二维扩散方程的虚边界积分表达式，然后利用虚边界元法进行数值计算。

The combustion events in the swirl chamber and the main chamber are processed differently. The combustion in the swirl chamber is broken into three phases: low temperature ignition, high temperature premixed combustion and flamelet diffusion combustion, while the combustion in the main chamber is only considered as flamelet diffusion combustion. The Shell ignition model, global Arrhenius equation and coherent flamelet model are used to describe low temperature ignition kinetics, high temperature premixed kinetics combustion and flamelet diffusion combustion respectively.

把涡流室式柴油机不同区域与不同时期的燃烧过程分开处理，将涡流室中的燃烧过程划分为三个性质不同但相互重叠的阶段：用Shell着火模型模拟的低温着火化学动力学反应阶段，用Arrhenius方程模拟的高温预混燃烧化学动力学反应阶段和用相关火焰微元模型模拟的扩散燃烧阶段，认为主燃烧室的燃烧只有相关火焰微元的扩散燃烧阶段。

Assuming infinite diffusion medium, based on the diffusion equation for prestressed concrete structure, and accounting for the effects of concrete chloride binding capacity, time dependence of diffusion coefficients, temperature and moisture, models of chloride diffusion in two-dimensional infinite body with both power function and constant homogeneous boundary conditions were formulated.

针对无限大的扩散介质，以综合考虑氯离子结合能力、氯离子扩散系数的时间依赖性和环境温湿度影响的实际预应力混凝土氯离子方程为基础，分别在常数和幂函数边界条件下，推导出二维氯离子扩散理论的齐次模型。

In this paper, a high order accuracy difference method is presented for solving unsteady convection diffusion equation by using Implicit Perturbation Finite Difference scheme. Firstly, we use the steady convection diffusion equation, the constant coefficients of this equation are expanded to power series of grid-spacings, then the high-order Perturbation Finite Difference scheme is obtained by determining the coefficients of the power series. Put this scheme on unsteady convection diffusion equations and modified it, the IPFD scheme is constructed.

本文利用摄动差分思想，对定常对流扩散方程中的空间微商系数进行摄动展开，展开幂级数系数通过消去摄动格式修正微分方程的截断误差项求出，由此获得方程的隐式摄动差分格式，将此方法应用于非定常对流扩散方程，并加以修正，得到该方程的修正隐式摄动差分格式。

This dissertation involves the study of the growth dynamics of colloidal particles under unequilibrium and irreversibility condition. Firstly, it is of interest to investigate whether the ideal diffusion or reaction-limited aggregation universal behavior can be observed for the initially polydisperse practical system of basic yttrium carbonate as well. The fractal structure of basic yttrium carbonate aggregate cluster was observed using transmission eletron microscopy. The aggregation kinetics of basic yttrium carbonate colloids was studed using dynamic 1ight-scattering techniques. At 1.00mol/l NaCl solution the fast diffusion-limited aggregation behavior was observed with an increase in the aggregate size over time described by a power law. The aggregates are characterized by a fractal dimension D=1.82. The disordered and ramified cluster is consisted of primary colloidal particles and tenuous and more open. These are in good agreement with those observed for other colloidal system such as colloidal gold (1.86), silica (1.85) and polystyrene latex (1.82) in diffusion-limited aggregation from the static and dynamic light scattering by Lin. Therefore ideal diffusion-limited aggregation behavior can be observed in practical polydisperse system as well. Smoluchwski and fractal theories were used to obtain the aggregation rate constant for initially polydisperse system for the first time.

本论文研究胶粒的非平衡不可逆聚集动态学，分为两个部分，第一部分是通过实验研究一个新的初始多分散的碱式碳酸钇胶粒实际体系中，聚集标度性质的普适性，即使用透射电子显微技术观测聚集粒子簇的分形结构，使用动态激光光散射研究碱式碳酸钇胶粒的聚集动力学，胶粒带电而产生静电排斥作用使得碱式碳酸钇胶粒处于稳定状态，当加入电解质NaCl溶液时，碱式碳酸钇胶粒间的Debye-Hückel屏蔽距离缩短，从而降低静电排斥能垒，引起胶粒发生不可逆聚集，加入电解质NaCl的浓度为1.00mol/l时，碱式碳酸钇胶粒进行快速聚集，经历扩散控制聚集机理，形成结构疏松、更为开放的分形聚集粒子簇，其分形维数为1.82，碱式碳酸钇胶粒聚集增长动力学遵循幂函数增长规律，与Lin等使用静态激光光散射和动态激光光散射测量硅胶(1.85)、金胶(1.86)和聚苯乙烯胶乳(1.82)在扩散控制聚集状态形成聚集粒子簇的分形维数值以及粒子簇聚集增长的动力学规律相一致，表明胶粒聚集标度性质的普适性质在初始多分散的实际体系中也是存在的，首次由动态激光光散射的实验数据得到初始多分散胶粒分形粒子簇的聚集速率常数，并且其值与Smoluchowski聚集速率理论预期相符。

In this paper,two nonlinear anisotropic diffusion filtering methods are presented and they are based on the multispectral anisotropic diffusion models proposed by Pope and Acton.We build a couple of new diffusion coefficients in partial derivative equation based on Tukey's biweight estimator error norm by recurring to the relationship between robust statistics and anisotropic diffusion incorporated with the nonlinear time-dependent cooling technique for gradient threshold.

在Pope和Acton提出的两个多光谱图像各向异性扩散滤波模型的基础上，通过各向异性扩散和稳健统计学的联系，建立了基于B iwe ight Estim ator误差模型的扩散系数，同时利用非线性退化技术对梯度阈值的改进，提出了两个基于各向异性扩散方程的非线性滤波方法。

Diffusion tensor imaging is a kind of new technique after diffusion weighted imaging.DTI can reflect anisotropy hydrone molecular diffusion features of damaged myeloid tissue through measuring apparent diffusion coefficient and fractional anisotropy.Accordingly,we can make more precise and allround estimate about spinal compression on microscopic scale.

磁共振扩散张量成像是继扩散加权成像后发展起来的一种新技术，它通过测量表观扩散系数及部分各向异性值来反映损伤脊髓组织的各向异性水分子扩散特征，从而在微观水平对脊髓压迫症做出更精确和全面的评价。

I'm strongly against the death penalty — it's an eye for an eye.

我不赞成死刑——这是以牙还牙的报复行为。

And to get you the support you need, we're enlisting all elements of our national power: our diplomacy and development, our economic might and our moral suasion, so that you and the rest of our military do not bear the burden of our security alone.

并给你们所须的支援，我们正徵召国家所有各种的力量：我们的外交及发展，我们的经济力量与道德劝说，所以你们与其他军人不须要孤独地负起国家安全的责任。