纯粹数学

D models are the most widely spread in the world of turbo-machinery for its simplicity, but they are indeed purely empirical correlations which not only fail to provide detailed information inside one or more components, but also require significant effort to recreate themselves if engine operating conditions or component representations change; quasi 3-D models have been the workhorses for compressor and turbine design for many years, and the primary benefit of using quasi 3-D system models is to facilitate the design and detail analysis of a particular component across the range of possible boundary conditions; Full 3-D models are gradually replacing quasi 3-D ones by virtue of requiring no exit flow angle model and loss model and being capable of predicting secondary flow in cascade.

零维模型由于使用时简单易行，因此在涡轮发动机的仿真中得到广泛应用，但零维模型作为纯粹的经验关系式无法反映部件内部的流动细节，并且一旦部件有少许改动则新特性的建立耗费巨大；准三维模型由于能够详细地提供部件内部的流动情况，方便设计而成为涡轮和压气机设计的主要工具；全三维数学模型正逐步取代准三维模型在涡轮设计中的主导作用，同后者相比前者能够预测叶轮机械内的二次流动，在粘性流计算时不需要气流角和损失的经验公式，因此拥有巨大的发展前景。

These things are mere abstractions.''That is all right,' said the Psychologist.

数学上所说的平面也是没有的，这些纯粹是抽象的东西。

However, as the name（read－only memory）implies, CD disks cannot be written onorchanged in any way.

然而，正如其名字所指出的那样，CD盘不能写，也不能用任何方式改变其内容。

Galvanizes steel pallet is mainly export which suits standard packing of European Union, the North America. galvanizes steel pallet is suitable to heavy rack. Pallet surface can design plate type, corrugated and the gap form, satisfies the different requirements.

镀锌钢托盘多用于出口，替代木托盘，免薰蒸，符合欧盟、北美各国对出口货物包装材料的法令要求；喷涂钢托盘适用于重载上货架之用，托盘表面根据需要制作成平板状、波纹状及间隔形式，满足不同的使用要求。