参数曲率

An adaptive grid scheme controlling cell area is used to generated grids in the divergent section of symmetric annular nozzle, and the generated grids are used in the flowfield calculation through the uncoupled way. The elliptic equations are used to generate grids in three dimensional regions of FDN divergent section, the source terms used in the equations employ a mathematical form which is independent of the boundary shape and of the boundary grid point distribution, the free parameters contained in the source terms are determined by the two restraint conditions, the intersection angle of transverse grid lines with boundaries and the local curvature of the transverse grid lines at the boundaries, and the interior grid distribution controlled directly by the grid point distribution assigned on the boundaries is realized, it makes the grid more clustering near the nozzle wall. For the generated grids in the whole computational regions have a good smoothness and orthogonality, the accuracy of calculation in the flowfield is ensured.

对轴对称的环形喷管采用控制网格面积的自适应网格方法对扩散段部分进行了网格生成，并通过非耦合方式应用于喷管的流场计算中；对强制偏流喷管扩散段内的三维区域采用椭圆型方程进行网格生成，方程中的源项采用了与边界形状和边界网格点分布无关的数学形式，源项内的自由参数由横向网格线与边界的交角及横向网格线在边界处的局部曲率两个约束条件来确定，实现了由边界上的网格分布直接控制内部的网格点，使壁面附近具有较密集的网格，并且在整个计算区域内的网格都具有良好的光滑性和正交性，从而保证了流场计算的准确性。

And the matching point pairs are obtained by comparing the Euclidean distance of the Zernike moments,which are computed around a circular neighborhood centered at the feature point.Then the transform parameters are computed through the correct mapping model.Finally,the weighed average method is used to achieve image mosaic.

该算法利用曲率尺度空间角点检测法提取特征点，通过比较各特征点圆形邻域Zernike矩的欧式距离得到匹配点对，然后利用正确的映射模型计算出变换参数，最后采用加权平均法得到图像的拼接结果。

The law of the influence of contractive angle of taper nozzles and curvature radius of convergence nozzles' convergent section on jet structure parameters is revealed, and it can provide a basis for optimization selection and design about laser cutting nozzles.

揭示锥型喷嘴收缩段收缩角、收敛型喷嘴收敛段抛物线曲率半径对射流的流场结构参数的影响规律，为激光切割喷嘴的优化选择和设计提供有效依据。标签激光技术激光切割会聚型喷嘴流场结构流体动力学 laser technigue laser cutting assemble nozzle jet structure hydrokinetics

A new curvature-based algorithm in free-form curve fitting was proposed to fit a 2D NURBS profile with an arc spline ,where a new form of curvature formula with matrix representation was also proposed,and then the arc spline tool path with G~(1) continuity was generated.

给出了一种平面曲线轮廓的圆弧样条拟合及刀具路径生成算法，该算法面向零件轮廓的光顺性刀具路径生成，通过应用曲线的曲率关系，对以NURBS表示的被拟合自由曲线按参数递增的方向用G1连续的圆弧或直线段逐段拟合，并生成相应的圆弧样条刀具路径，从而实现零件曲线轮廓表面的光顺加工。

In this paper, the method of small parameter is used to discuss the problems of stress concenration in the neighborhood of a concentrated load or a circular hole on a shallow shell of elliptic paraboloid.

本文采用小参数解法讨论了椭圆抛物面扁壳在集中荷载和圆孔附近的应力集中问题。所取的小参数为ε＝／这里Kx和Ky是沿x和y方向的曲率）。

This paper studies the relationship between the approximate confidence and the statistical curvature in nonlinear exponential family regression models with linear restriction from geometric point of view.

本文从几何的观点，研究了带有线性约束的指数族非线性回归模型下参数的近似置信域与统计模型曲率之间的一般联系，获得了参数的近似置信域。

In order to improve the control performance, when the image distortion is too large resulting from camera obliquity, these parameters are transformed from image coordinate to robot coordinate through projective transformation, while parameters such as position and curvature are not necessarily provided.

为改善控制性能，当由于摄像机倾角较大而引起的图像畸变较大时，利用射影变换把参考轨线参数从图像坐标系映射到机器人坐标系，而无须提供位置、曲率等参数。

Through the new research methods, this thesis has made the following contributions in this field: 1. For the first time the curvature radii and relative angles of a planar continuous curve at discrete points are chosen as local parameters to represent the curve, which reflect clearly the local geometrical characteristics of the curve and are easy to be dealt with.

借助于新的研究方法，本文在这一领域作出如下贡献：（1）首次提出用曲线上离散点处曲率半径和相对转角作为局部参数表示平面连续曲线，直观地反映曲线各个局部的几何特征，且便于曲线的修改和变换，并通过机构运动分析，快速求出机构轨迹的这两个局部参数。

The main contents and achievements are summarized as following: 1. The principle of tension leveling of metal strip is described systematically using relative tension and relative curvature on the basis of plane hypothesis including the stress distribution on the section, the condition to undergo plastic longitudinal elongation, the calculation of longitudinal elongation, the change of tension along the strip etc.. 2. The tension leveling process of metal strip on a multi-roll arrangement is investigated detailed by nonlinear finite element method and many rules to guide the strain, deformation, stress and bending moment are discovered and illustrated.

本文的主要内容和成果如下： 1、以平面假设为前提，采用解析分析方法，建立了以相对张力和相对弯曲曲率为基本参数的平面应变金属带材拉伸弯曲变形基本原理较为系统的描述，描述涉及到应力分布与两个基本参数的关系、带材塑性延伸的边界条件、带材延伸率的计算、带材张力变化的计算等。

This kind of subdivision, although not economical in terms of the number of quadrilaterals, is precisely what we want for obtaining the parameters, i.e. a uniform, geometry/curvature based distribution of quadrilaterals is more important to get good parameters than the minimum number.

这种再分方法尽管在四边形的数量方面不是很经济，但它可以使我们得到精确的参数，就是说对于要得到一个好的参数来说，一个统一、基与几何或曲率的四边形分配比最小数量更重要。

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。