参数曲线

In this paper, based on the 1st order Taylor's expansion approximation interpolation, a realtime parametric curve interpolation algorithm is proposed in this paper, which can automatically adjust feedrate to confine the contour error within a given tolerance.

本文在一阶泰勒展开近似插补方法的基础上，给出了一种能够自动调整进给速度，将轮廓误差限定在允许范围之内的参数曲线的实时插补方法。

Specifically, we apply the polar form in the conversion between triangular Bezier surfaces and rectangular Bezier surfaces. This problem helps us to understand the theory of polar form in a unified way. At the last half of this paper, we consider the problem of geometric continuity of parametric curves and parametric surfaces.

我们利用Polar形式实现了三角Bézier曲面和四边Bézier曲面之间的相互转化，同时通过应用，我们对Polar形式也有了一个统一、全面的认识；论文的后半部分考虑了参数曲线曲面间的几何连续性问题。

Our study shows that it is a good choice to apply generalized rational parametric curve to interpolate and fit unorganized data, because it provides higher numerical stability by appropriately adjusting the support of basis functions.

最后应用广义有理参数曲线对散乱数据进行插值拟合，它可以通过调整基函数的支撑域来优化方程的系数矩阵，因此提供了更高的数值稳定性。

The error compensation is introduced in the interpolation algorithm to increase the interpolation point's solution precision of the parametric curve, and the reasonable simplification of the compensation expression is carried in the solution process to decrease the calculation load of interpolation.

通过引入误差补偿值以提高参数曲线插补点的求解精度，在求解过程中对误差补偿值进行合理简化以降低插补计算量。

Experiments show that C-B spline curve, uniform B-spline with shape parameter, hyperbolic polynomial uniform B-spline with shape parameter and trigonometric polynomial uniform B-spline with shape parameter can be used to produce some frequently used free form curves in the industrial field when the shape parameter is assigned with some specific values. This process is simpler than producing these free form curves by using controlling vertex.

实验证明，C-B样条曲线、带形状参数的均匀B样条曲线、带形状参数双曲多项式的均匀B样条曲线、带形状参数三角多项式的均匀B样条曲线都可利用形状参数的特定取值表示一些工业领域常用的自由曲线，这比起用控制顶点表示同样的自由曲线更为简单。

It chooses the vitta, the pump, and the sucker-rod assemblage in reason from the dimensionless quality curve, and the sucker-rod assemblage sheet.

以产量为目标根据无量纲参数曲线、抽油杆柱组合数据表来合理选择抽油泵、油管、抽油杆柱组合，并对工作状态进行预测。

The critical curves of linear shimmy systems are determined by optimizing the complex eigenvalues. This method can be used to analyse stability of linear shimmy systems with the arbitrary degrees of freedom and to extricate designers from the tedious algebraical derivation in the early shimmy stability analyses.

并使用&复特征值优化分析方法&确定线性摆振系统的各种临界参数曲线，这种方法可以分析任意多自由度的线性摆振系统的稳定性，免去了以往摆振稳定性分析中冗长的代数推导。

In this thesis, we mainlystudy some problems on approximate implicitization and piecewise algebraic varieties.

本文主要针对参数曲线曲面的近似隐式化和分片代数簇的某些问题展开研究。

The polarization curve is not sufficient for a reliable and unique validation of a PEMFC model since different parameters can lead to an identical polarization curve. A three-step validation approach is proposed for a complete and unique validation. These three steps are:(1) validated by the global polarization curve,(2) validated by the local current density distribution curve, and (3) validated by the cathode over-potential and anode over-potential versus current density curve. The results from the comparison of four flow-fields show that the PEMFC performance of the flow-fields decreases in order by interdigitated, metal foam, pin-type and parallel.

通过PEMFC参数敏感性研究发现，PEMFC性能受多种参数的影响，这些参数可分为非敏感性参数、敏感性参数和高敏感性参数；与阳极侧参数相比，PEMFC性能对阴极侧的参数更敏感；不同参数值的组合可以得到几乎完全相同的极化曲线，因此电池的极化曲线不足以用于验证数学模型的唯一性与可靠性；为验证PEMFC数学模型的唯一性与可靠性，提出了模型验证的三步法：极化曲线验证、局部电流密度验证和阳极总过电位与阴极总过电位验证。

Based on the virtual prototype technology and simulative software platform Pro/E, the double rotating shaft supporting mechanism of wind tunnel testing model was designed and developed, and the mathematical model of angle control was established.

基于虚拟样机技术及仿真软件平台Pro/E，设计开发了风洞试验模型的双转轴支撑机构，建立了角度控制的数学模型，实现了机构的虚拟样机设计和运动学仿真，获取了被测试验模型运动情况的运动参数曲线，并对双转轴机构实施了干涉的动态检查，为双转轴机构设计方案的交流与评估，以及双转轴机构的制造与应用奠定了基础。

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。