参数表示

Properness of a parameterization is a basic property of rational parametric curves and it has been well studied when the coefficients of the parameterization are rational. However, such coefficients in engineering and CAGD are often represented with float numbers with errors.

有理参数曲线的恰当性是曲线的基本性质，虽然其在有理系数情况下已经有完备的结果，但在工程和CAGD应用中常常得到带误差浮点系数的有理表示形式。

Absolute open flow is a important index of appraising oil/gas well production capacity,and often used in oil/gas well classification、proration and dimensionless parameters in other equations and so on,it denotes oil/gas productions under full openness of well bottom.

无阻流量是评价油气井生产能力的重要指标，也常用于油气井分类、配产和其它公式中参数的无因次化等，它表示井底在完全敞开的情况下油气井的产量。

Furthermore,it can represent the elliptic curves,parabola and other quadratic curves without using rational form.

给出了一种基于三角函数的类三次参数曲线，该曲线不仅具有类似于三次Bézier曲线的诸多性质，而且无需有理形式即可精确地表示椭圆、抛物线等二次曲线。

The change of parameter {a, b, c, d} with temperature in double exponential function can be expressed as a quadric polynomial function of temperature.

双指数函数中的参数{a， b， c， d}随温度的变化可以表示成温度的二次多项式函数。

The results showed that the coefficient of raicel decreased firstly in a short distance, and then kept stable form radicel base to radicel apical.

通过对胚根分支系数研究表明：从根基部到根尖，呈现出先递减，然后保持稳定的趋势，采用经验分布函数表示；同时，用四种分支类型已能描述玉米胚根分支特征，且它们的特征参数在一定范围内随机分布。

This random walk simulation can represent the dispersion process at different length scale, but the parameter of simutation has different means.

这种随机游动模拟能够表示不同尺度上的弥散过程，但其对应的模拟参数具有不同的意义。

We extended the Safety Margin theory, the flight parameters transferred to the singular space through the SVD method. This conception created the Safety Margin Terrain and showed the geometry properties of current flight.

而将飞航安全几何化的观点再做推展，透过奇异值分解的方法，将参数转换至奇异空间，再利用几何方程式，拟合飞航安全裕度於奇异空间中的曲线，求得安全裕度地形，并由此模型计算出每一航班之几何变化，并藉由此方法可求得当下飞航安全裕度的几何特性，表示当飞航安全的状态。

First, this thesis introduces basic theory of CBR , and studies many aspects of typical part design case , such as case representation, case retrieval, retain etc. Second, regards design code as case code in order to integrate the case with geometrical and non- geometrical information, and realizes the parametric modifying function for 3D solid model in the condition of Pro/E. Third, for the purpose of making true of system's aided design requirement, this thesis brings forward to create part design knowledge base with AI language CLIPS, and integrates the rule based KB into the system; finally, collects and summarizes the knowledge of shaft,gear,sleave, and a sample with ladder—shaft is shown in order to verify the correction of theory research.

首先，本文介绍CBR技术的基础理论，并重点研究典型零件案例的表示、检索、修改等功能；其次，以零件设计编号为案例编号实现对案例的几何与非几何信息的集成，并实现了三维实体模型在Pro／E环境下的参数化修改功能；再次，从系统辅助设计功能要求出发，提出将基于规则的知识库嵌入到系统内部，用人工智能语言CLIPS建立零件设计知识库；最后，对轴类、齿轮类、盘套类零件案例知识进行收集、总结，并通过阶梯轴设计实例验证了理论研究的正确性。

To these parameters we can assign various values according to the problem considered. And when parameters are assigned some special values, some graphical representations are the special cases of our graphical representation.

灵活性是说我们可以在不同的情况下取不同的参数，以达到最优效果；概括性是指它包含许多已有的表示方法为特例。

This parameter is Sphericity, which represents the degree of similarity between two triangles.

这个参数就是球度，表示了两个三角形之间的相似度。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。