查询词典 diffusion equation

The diffusion of mass or heat across two phases is extensively involved in chemical processes. Because of the effect of this kind of diffusion, there will be a inhomogeneous distribution of material concentration and then a gradient of interfacial tension will be occured on the interface of the two phases. When the gradient tends to a certain value, the natural convection would be induced derivatively, and orderly convective cells would appear in the system simultaneously. This is the so-called Marangoni phenomenon.

在化工过程中，广泛涉及到两相间的质量或热量扩散，由于这种扩散的作用，将在相界面处产生物质浓度的不均匀分布，从而出现界面张力梯度，这种梯度达到一定值以后，将出现派生的自然对流运动，并且在系统中呈现有序的对流胞结构，这就是所谓的Marangoni现象。

A new method for determination of diffusion coefficient with diaphragm-cell has been suggested, by which the differential diffusion coefficient can be directly determined and a tentative experiment has been done.

提出了膜池测定液相扩散系数的新方法。这一新方法能够直接测定溶液的微分扩散系数，并采用标准物系对上述方法进行了初步的实验验证。

Objective: To evaluate the feasibility of diffusion-weighted imaging and apparent diffusion coefficient in diagnosis of cervical cancer.

目的：分析正常子宫宫颈3层结构及宫颈癌的扩散加权成像特点，探讨其及相应的表观扩散系数对宫颈癌的诊断价值。

Furthermore, social progress and IT advancement strengthen the urban spatial diffusion. Such diffusion effect and the increasingly constant exchanges between city and its surrounding areas accelerate the extension of city and the integration of urban and rural areas.

随着社会进步和和信息技术的发展，加强了城市的空间扩散能力，城市空间扩散的效应和城市与周边区域间的交流日益频繁，加快了城市向外的拓展，促进了城乡间的快速融合。

By automatically selecting the optimal diffusion constant and iterative number, the filtering process is totally automatic and does not require any operator assistance and the diffusion is suppressed or stopped at boundaries and edges and small structures are retained.

正是在这样的背景下，本研究针对计算机集成相控HIFU治疗计划中的两项关键技术：序列医学断层图像的分割及其体视化技术，进行了理论研究和算法的设计。

Illustrative results are presented for the radiation dose and dose profile with activity distributions: uniform, determined by steady-state diffusion into the target volume, or determined by steady-state diffusion with a constant rate of loss of activity from the target.

计算程序用Visual Basic V6.0编写，在微机上运行。为了验证计算结果，将均匀分布条件下的计算结果分别与文献报导的结果比较，发现它们是一致的。

Gas diffusion electrode was applied in the reaction system in order to weaken control process of diffusion.

比较了两种方法制备的气体扩散电极对反应控制步骤的改进效果。

Analysis of its behavior shows that the generalized diffusion process combines properties of both forward and inverse diffusion.

其行为的分析表明，广义扩散过程结合了这两个属性正，逆扩散。

The hot-rolled composite is a diffusion process, and the diffusion range of the elements is about 50 μm.

热轧复合为扩散型冶金结合，元素扩散范围在50μm范围内。

Fourth, in the view of technological system, the intrinsic characteristics of innovation diffusion are embodied in the diffusion process of technological knowledge.

所转移的技术知识涉及的不仅是边际交易费用为零的纯粹科学知识。

The changes of the HAF after liver injury may be related to the volume of blood loss, the intraabdominal pressure and the pneumoperitoneum duration.

肝撞击伤伴失血后肝动脉血流量的变化与失血量、气腹压力以及气腹持续时间等有密切联系。

Reneging on our commitments to the world's poor cannot be an austerity measure, she said.

放弃我们给世界上的穷国的承诺不能成为一种紧缩措施。