二次曲面

The conicoid fitting method and the neural networks method are used for this purpose, but each of them has its advantages and disadvantages.

转换GPS高程通常采用二次曲面拟合法和神经网络方法，但这2种方法各有优缺点。

Use VTK pipeline mechanisms conicoid mapping, and production of contour lines.

详细说明：使用VTK的管道机制实现二次曲面的绘制，并制作等高线。

The conicoid fitting method used for transforming GPS elevation, and the basic structure and mathematic formulas of BP algorithm of neural networks are introduced briefly in this paper.

简要介绍了转换 GPS高程的二次曲面拟合法，以及神经网络 BP算法的基本结构和数学公式。

Then, the model error of the conicoid fitting method is detected by the BP algorithm of neural networks. Application to a practical project shows, the feasibility of the method, and some conclusions of practicable value are drawn.

然后，尝试用 BP神经网络方法来探测二次曲面拟合法的数学模型误差，通过某工程实例，证实了该方法的可行性，并得到了一些有工程应用价值的结论。

The high vertical resolution is achieved at a larger sampling distance when interpolation algorithm is adopted to reconstruct the 3D profile and the conicoid fitting technique is used to calibrate for the system error in the data processing.

在数据处理上，采用了内插值三维重构算法，以及二次曲面拟合的系统误差校正算法，可以在较大的采样间距下获取较高的测量精度。

Sphere fitting method, conicoid fitting method and line scanning curve fitting method are used to approach system error for the first time. The effect on the measurement error of each method is also analyzed.

首次利用球面拟合法、二次曲面拟合法以及行扫描曲线拟合法去逼近系统误差，并分析了各种方法进行系统误差校正时对最终测量误差的影响。

The capital parameters of the optical system are f′=1 600mm,2ω=18°×0.148°, F/number=F/10,and all surfaces are conicoid.

光学系统的基本参数为：焦距f′=1 600 mm，视场角为2 w=18°×0.148°，相对孔径为1／10，3个反射面均为二次曲面。

Normally, the conicoid fitting method and the neural network method are used for converting a GPS height into a normal height.

转换GPS高程通常使用二次曲面拟合法和神经网络方法，但这两种方法各有优缺点。

The corneal models of the emmetropic and myopic eyes and corrected eye models were presented and the relevant corneal ablation model was also given. The results show that the maximum ablation depth located at the center is about 26.5 μm.

结果表明：基于人眼光学模型的角膜双二次曲面模型，符合角膜的面型特点，适合临床实际应用，可为波像差引导的个性化角膜切削方案提供更适用的数字化模型。

In this paper, the effects of the rigid body motions and low frequency surface errors on the image quality were analyzed. Quadratic equations were used to build the mathematical model of the Wolter type I and II X-ray telescopes and reduce the computational complexity of ray tracing. With the help of a self-developed optical surface analysis code, the effects of the perturbations of the mirrors on the image quality was analyzed and the growth of the image spot formed by deformed telescopes was calculated, this is important for giving the reasonable fabrication tolerance.

在本篇文章中，详细分析了刚体运动误差和低频表面误差对成像质量的影响；使用空间解析几何学的二次曲面方程建立Wolter I、II型X射线掠入射望远镜镜片的数学模型，降低光线追踪的计算复杂度；借助自主开发的光学仿真软件分析了国内研制的X射线成像望远镜的刚体运动误差和低频表面误差对成像质量的影响，计算出像点艾里斑半径均方根值随误差变化的增长率，对工程上提出合理的制造公差的误差容限有重要的指导意义。

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。