几何轨迹

Some basic equations of dual beam scan are derived,such as,the position vector for the incident point,the scalar expression for reflected ray,scan pattern on observation plane ect.

文摘：应用几何光学理论研究了多光束转镜扫描场的非对称性，导出多光束扫描入射点位置矢量、反射线标量表达式、观察面上的扫描轨迹方程，并研究了扫描远场的非对称性。

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。

By analyses of geometry characteristies of various cutters and workpieces,the methed of application of the property to improving the algorithm on calculating the cutter－ contact point trace is presented.

对各种形式的刀具与工件的几何特性进行了分析，阐述了该性质在改进刀位点轨迹算法中的应用方法。

Based on the geometry constraint and dimensiondriving technique, a 3-UPU parallel simulation mechanism is created. Then a 3D free surface and a guiding plane of tool path are constituted, with the 3-UPU parallel machine tool combined, a novel 3-UPU simulation parallel machine tool for machining a 3D free surface is created.

通过几何约束和尺寸驱动技术，先建立3-UPU并联模拟机构，再构造任意3D自由曲面和刀具轨迹的引导平面，与3-UPU模拟并联机构合成，得到用于加工任意3D自由曲面的模拟并联机床。

Based on the geometry constraint and dimension-driving technique,a 3-UPU parallel simulation mechanism is created.Then a 3D free surface and a guiding plane of tool path are constituted,with the 3-UPU parallel machine tool combined,a novel 3-UPU simulation parallel machine tool for machining a 3D free surface is created.

通过几何约束和尺寸驱动技术，先建立3-UPU并联模拟机构，再构造任意3D自由曲面和刀具轨迹的引导平面，与3-UPU模拟并联机构合成，得到用于加工任意3D自由曲面的模拟并联机床。

In comparison with the computation point by point according to Hencky stress equations, determination of the stress in slip line field by use of the geometrical mapping is clear and simple.

文献〔1〕〔2〕〔3〕在Prager极点轨迹基础上提出了一种摆线映射法，这是滑移线场在口一，应力平面上的一种几何映射，其图形由两族相互正交的摆线构成。

Resorting to the Roberts-Chebyshev theorem,we replace the two cranks of a crank-rocker cognate mechanism with a double bar,which is required to satisfy certain geometrical and motion conditions,and we change the mechanism thus reformed into a geared five-bar mechanism so that one of its links can fully rotate with the link connected with it.

借助于Roberts-Chebyshev定理，将曲柄摇杆轨迹同源机构的两曲柄分别用一双杆组代替，并要求双杆组满足一定的几何尺寸条件和运动条件，使变形后的机构为齿轮五杆机构，且满足机构的一个连架杆以及与其相连的连杆能够整周转动。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。