坐标平面

The paper presents an efficient approximate algorithm for Convex Hull of very large planar point set.

提出了一种计算海量平面点集凸壳的快速近似算法——点集坐标旋转法。

Closest point to the problem is for two-dimensional coordinates of the point of the problem, the algorithm is to be planar point set on the S linear divided roughly equal to the size of two sub-sets of S1 and S2, we selected a vertical line l : x = m as a separate line.

最接近点对问题是求二维坐标中的点对问题，该算法是为了将平面上点集S线性分割为大小大致相等的2个子集S1和S2，我们选取一垂直线l：x=m来作为分割直线。

Firstly basic interpolations are obtained from planar circle interpolation by the point by point comparison.

首先使用逐点比较法作平面圆弧插补获得基本插补量，然后以三维坐标变换将基本插补量变换成为空间椭圆的插补量。

According to the plane cross section assumption, configuration of a rod is expressed as a history of the cross section with arc coordinate. A special solution which stands for equilibrium in straight line state is obtained from differential equilibrium equation. Linear perturbation equation is derived and its general solution is obtained in which the integral constants are determined by constrained conditions at two ends of the rod. The condition of existence of non zero solution of the integral constants gives to the Greenhill formula of exact elastic rod model, which shows that the boundary of stable area is a closed curve and of symmetry, and inference of shearable and extensible to stability of the rod is depend on three factors: difference between flexibility of shear and extension of a section of the rod, bending stiffness and the length of the rod.

基于平面截面假定，弹性杆的位形表达为截面的弧坐标历程，根据平衡微分方程得到了两端受力螺旋作用时的直线平衡特解，导出了线性化扰动方程及其通解，积分常数根据两端铰支时的边界条件确定，并根据其存在非零解的条件得到弹性直杆精确模型的Greenhill公式，表明稳定域为一对称的封闭区域，拉/压和剪切对稳定性的影响取决于：拉/压柔度与剪切柔度之差，抗弯刚度和杆长这三个因素

The improved model can combined the plane coordinates of plane net and the height of height net to calculate seven transformation parameters with other three dimensional coordinate system.

改进后的模型联合平面控制点的坐标和高程控制点的高程求解与其他3维空间坐标的7个转换参数，不需要3维已知点。

In the measurement of work, the first test with control meaning the area to choose some point to form a certain geometrical form the skeleton of the surveyed area, with a relatively accurate means of measurement and calculation methods, in a unified coordinate system to determine these points plane coordinates and elevation, and then based on it to determine the point and other ground points, or construction setting, or other measurements.

在测量工作中，首先在测区内选择一些具有控制意义的点，组成一定的几何图形形成测区的骨架，用相对精确的测量手段和计算方法，在统一的坐标系中，确定这些点的平面坐标和高程，然后以它为基础来测定其他地面点的点位或进行施工放样，或进行其他测量工作。

The plane adopts the joint method of both the finite element and the finite difference to divide plane domain by means of irregular triangular net in order to fit topography and coastal line complicated sea zone; Vertical application σcoordinate conversion and the finite difference method.

平面采用有限元法和有限差分法相结合的方法，用不规则三角形网格剖分计算域，以适应地形和岸线复杂的海区；垂向应用σ-坐标变换及有限差分法。

Distortion discipline of line heating for automatic processing is researchedThe main influence factors of shell plate forming by line heating are analyzed. Based on the analysis of measured data processed by the experiment machine of line heating, thickness of plate, length of heating line, processing speed and shrinkage are regarded as 4 dimensions, and the methods of vectors mapping, plane projection and conversion of coordinates are used to build mathematical models for local surface shrinkage of different thickness and processing parameters.

1研究了自动化加工水火弯板变形规律分析了水火弯板加工成型的主要影响参数，在对水火弯板实验机加工测量数据分析的基础上，以板厚、加热线长度、加工速度和收缩量作为4个维度，应用向量映射，平面投影、坐标转换方法建立了不同钢板厚度的局部表面收缩量和加工参数的数学模型。

It proposes idiographic schema to rationally choose projection zone and perspective plane. The choice of projection zone and perspective plane in the establishment of plane coordinate system of GPS network in Datong mining area has validated that the schema is feasible.

提出了合理选择投影带和投影面的具体方案，并以大同矿区GPS网平面坐标系统建立中投影带和投影面的选择实例验证了该方法在实际应用中是切实可行的。

This paper analyses how the electricity vector orientation of the normal incidence plane polarized light or garden polarization light is altered by quarter wave plate by making use of Jones matrix of polarizer.

用坐标变换法解出偏振器件一般情况下的Jones矩阵，利用偏振器件的Jones矩阵分析四分之一波片对正入射平面偏振光和园偏振光的偏振态的改变，指出获得和判断椭园和园偏振光的方法。

Plunder melds and run with this jewel!

掠夺melds和运行与此宝石！

My dream is to be a crazy growing tree and extend at the edge between the city and the forest.

此刻，也许正是在通往天国的路上，我体验着这白色的晕旋。