角曲线

Based on varying process of generator terminal parameters after excitation fault, shortages of excitation protective principle of static stability boundary and asynchronous impedance boundary are analyzed. It proposed that excitation fault research relates to large-disturbance stability. Because dynamic power-angle character of generator after excitation fault is non-sinusoidal, there are differences between dynamic power-angle character and static state power-angle character. So it isn't ideal to protective operation result based on small-disturbance stability and static stability boundary criterion. At the same time, it proposed that asynchronous boundary impedance criterion is a constant reactive power circle moving adown j Xd′. It can ensure complete loss-of-excitation generator measuring impedance enter into the circle, but can't ensure the other condition measuring impedance including impossible losing synchronism enter. So loss-of-excitation protection would be maloperation when system voltage drops short and recovers or generator rejects load.③Based on stability principle, it puts forward setting conditions and calculation method of generator loss-of-excitation protection by direct measuring power-angle.

以励磁故障后发电机端的相关参数的变化为基础，通过对以静稳定边界和异步阻抗边界作判据的两类三种现行励磁保护在原理上存在的缺陷分析，发现：励磁故障是一个大干扰稳定性问题，励磁故障后的发电机的动态功角特性与静态功角特性有很大的差异，已远非正弦曲线，因此基于小干扰稳定性原理、以静稳定边界作判据的保护必然动作不理想；异步边界阻抗判据是一个下移j Xd′的等无功阻抗圆，它可以保证完全失磁后的发电机测量阻抗能进入该阻抗圆，但不能保证完全失磁之外的其它状态不会进入该阻抗圆，因此在系统电压短时下降或发电机突然甩负荷等情况下可能启动该保护使之误动。

For the key of vector- Distance algorithm , Curve fitting is used for the derivation of deviation angle algorithm, demonstrating the feasibility of deviation angle Algorithm and the error analysis.

针对矢量距离算法的关键，采用曲线拟合对计算偏离角的关系式进行了推导，论证了偏离角算法的可行性，对算法进行误差分析，用归纳的方法推导出计算磁短节中点与直井之间距离的关系式。

In this paper it is given a more effective formula about the direction angle of the main plane in the plane stress state.2. To introduce the principle and method for drawing 3-D graph with the compuer and for checking up with the computer cursor,to give outline of expressions of 3-D curve,outline of cursor meterage of well depth,well deflection angle and direction angle at any section.

介绍了在实践中总结出的计算机绘制与光标检测3维图形的原理和方法，给出了3维动态图形到屏幕坐标的变换式、各测点的平滑连接方法以及描绘与检测井眼轨迹曲线的典型应用，实现了空间井眼轨迹曲线的任意旋转、投影和给出了任一井段的井深、井斜角和方位角的光标检测软件。

In this chapter, three kinds of target recognition methods are performed, which are:①Target recognition method based on the description of polarization parameter plane. The echo polarization states of target are projected onto the polarization state plane described by the ellipticity ε and the tilt angle τ of the polarization ellipse, the change of parameter following ferquency becomes the chart. According to the changing trait of the chart, the multidimensional polarization feature space of target has been contructed. Furthermore, a series of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.②Target recognition method based on the description of Poincare polarization sphere. The echo polarization states of target expressed by Stokes vector are projected onto the Poincare polarization sphere. The conception of polarization ferquency stability, which is used in describing the dynamic distribution characteristics of the target echo polarization states on Poincare polarization sphere, has been defined. A group of polarization feature parameters used in designing the structure of target recognition device are extracted, and they are insensible to the posture of target.③Target recognition method based on the description of frequency sensitivity. In accordance with the conception of the polarization state distance defined on Poincare polarization sphere, the frequency sensibility of the physical structure property of target has been investigated, the frequency distribution feature curves in PSD domain are obtained, and targets'features are extracted by means of the curve-fitting method with Least Square Criterion.

这章具体研究了基于三种极化散射特性描述的相应的目标识别方法：①基于极化参数平面描述的目标识别方法，将目标回波极化状态投影到以极化椭圆参数，即椭圆率角ε和倾角τ表征的极化状态平面上，参数随观测频率的变化就形成了图，根据图的变化特点构造了目标的多维极化特征空间，并提取了不敏感目标姿态变化的极化特征参数组来设计目标的识别器结构；②基于Poincare极化球面描述的目标识别方法，采用Stokes矢量表征目标回波的极化状态，并将其投影到描述极化状态的Poincare极化球面上，定义了极化频率稳定度的概念用以刻画目标回波极化状态在Poincare极化球面上的动态分布信息，提取了准方位不变性的目标极化特征，最后设计了目标的识别器结构；③基于频率敏感性描述的目标识别方法，通过在Poincare极化球面上所定义的极化状态距离的概念，研究的是复杂目标物理结构特性对探测信号频率的敏感程度问题，获得了在极化状态距离下的频率分布特性曲线，采用最小二乘估计曲线拟合方法，它既用于极化特征的降维，同时又直接将拟合参数作为目标的分类特征。

First, a map between the cones and tangent surface on C-Bézier curve und two-dimensional plane is found respectively and then a ruled surface between two Bezier curves is constructed and a sufficient condition on its developablity is given.

zier曲线上锥面、切线曲面的展开方法。然后，构造两条空间B？zier曲线上的直纹面，给出了它成为可展曲面的一个充分条件，并通过保角保长原则，将其贴合到平面上。

The vaulter seemed to start to swing to inversion as he swung approaching a constant visual distance to one stationary point in the space.

由髋角相对於眼睛水平位置变化曲线，发现当眼睛到达某一固定位置时，同试跳高呈现曲线重叠现象，与前摆脚往上开始动作时间相同。

First, the cross section of a boxlike girder is discretized into stiffened elements and corner elements, then the FEM program is compiled to calculate the curve between stress and strain of every stiffened element.

加筋板单元是船舶与海洋工程等箱型梁结构的主要组成构件，首先将箱型梁剖面离散成若干加筋板单元和角单元，利用非线性有限元方法逐一计算加筋板单元的应力—应变关系曲线，然后再用逐步破坏分析法得到整个结构的弯矩—曲率曲线，从而求得其极限弯矩。

For feature extraction, this dissertation studies Barnard algorithm for Edge Point extraction and SUSAN algorithm for Corner extraction, Afterward, I put forward a method to extract inflexions, straight lines and curves based on Freeman Differential Code. Thus the use of Freeman Code can be extended and there will be more approaches to finish stereo correspondence.

在特征提取部分，本文对传统的Barnard边缘点提取、新近的SUSAN角点检测等技术做了详细的分析和研究，并在此基础上提出了基于Freeman差分码的多特征提取方法，包括拐点、直线及曲线，而且提取的直线利用多直线段分解法进行拟合，提取的曲线利用B样条技术进行拟合，最终形成有意义的轮廓。

During the pipe pushing construction of the parallel steel water pipeline of Beidu-Yanger pipeline project in Ningbo, the pushing force in main pushing power station appeared unusual increasing and the construction had to be interrupted. Through the analytical comparison between theoretical and practical pushing curves as well as the analytical comparison between the tool pipe track and the form map of pipeline resting in soil, it was found that the excessive pushing force in main pushing power station was caused by excessive deviation adjustment angle which enabled the pipeline to over bend in a short distance.

在宁波市北渡－雅戈尔原水D1800mm钢管复线工程顶管施工中，出现主顶动力站顶力异常增大的现象，影响继续顶进施工，文章针对这一情况进行分析研究，通过理论顶力曲线与实际顶力曲线以及工具管所经轨迹与管道在土层中静止时的形态图的分析比较，得出主顶动力站顶力过大是因为在纠偏过程中纠偏角度过大，使管道在短距离内过度弯曲引起的。

The power of motor is positive proportion to square root of equality of square pure torque .the pure torque is combined by suspension point torque and balancing weight torque ,so the change of suspension point's motion law and balancing weight offset angle can causes pure torque variation .especially, the suspension motion law is decided by configuration curve of hinder heaven sheave .so the paper has emphatically studied and analysis the law that the configuration curve of hinder heaven sheave brings the change of pumping unit energy-saving .

电机功率与减速器曲柄轴净扭矩均方根成正比，减速器曲柄轴净扭矩是由悬点载荷产生的扭矩和平衡重产生的平衡力矩合成的；改变悬点运动规律和平衡重的滞后角可以引起净扭矩的变化，其中悬点运动规律是由后天轮曲线决定的，因此，本文依据此原理着重研究分析了后天轮曲线影响抽油及节能的变化规律。

The basic concept of FOP can be summarized as to further optimize effective prescription according to the standard of curative effects and with the aid of modern science and technology and theories of traditional Chinese medicine.

其基本内涵可概括为：以确有疗效的中药复方为研究对象，以现代科学技术和传统中医药理论为技术支持，以该复方所治病证的药效响应为评价标准，以优化重组疗效更优的新复方为研究目的。

Ever since our world has been a world, native forests have been indiscriminately exploited by man.

自从我们的世界一直是世界原生森林被任意剥削人。