Several space physics missions that are being designed or flown need spacecrafts flying in a tetrahedron configuration about a highly elliptical reference orbit.
采用基于轨道根数的相对运动模型,分析了参考轨道根数对四面体性能指标——质量因子和平均边长的影响;假设某一航天器运行于参考轨道,提出了以其他三个航天器的15个相对轨道根数为设计变量,目标函数兼顾质量因子和平均边长的四面体优化设计方案,并将其应用于第一阶段MMS任务的四面体构形设计中。
Boundary surface of 3-D region is divided into quadrangle mesh, the surface integral in Gauss formula is treated with finite element method.
分析求积公式中三阶行列式意义,提出了简单五面体有向体积概念,推导出计算四边形网面所围立体的有向体积叠加方法。
a prism whose bases are quadrangles.
底面是四面形的棱柱。
A plane figure with four sides and four angles.
四边形有四个边和四个角的平面图形
a tetrahedron with four equilateral triangular faces.
有四个等边三角形面的四面体。
Put four small triangles under the big rectangle.
把四个小三角形放在大长方形的下面。
Algorithm for smallest quadrangle encasing box of convex polygon
凸多边形最小面积四边形包围盒算法
a polyhedron whose faces are trapeziums.
由不等边四边形面组成的多面体。
A FOUR-NODE QUADRILATERAL MEMBRANE ELEMENT FORMULATED BY THE THIRD VERSION OF THE QUADRILATERAL AREA COORDINATE METHOD
用第三类四边形面积坐标构造一个四结点四边形膜元
a parallelepiped bounded by six similar faces (either rhombuses or parallelograms).
有六个面的平行四面体（或是棱形的或是平行四边形的）。
A four-sided planar figure with a diamondlike shape; a rhombus that is not a square.
菱形钻石形状的四边平面图形；不是正方形的菱面体
A square is formed by four couples who stand facing the center of the stage.
四对男女面朝中心站成一个正方形，
Multi-layered Quadrangle Assimilation of True Surface of Object
物体表面真实感的层次四边形拟合
a square has four sides, a cube six.
正方形有四个边, 立方体有六个面。
Internal Force Analysis of Tensile Membrane Structures by Curved Quadrilateral Element;
采用曲面四边形单元分析张力膜结构
Flat surface four node model big transform the long to breadth ratio analysis
平面四节点模型的大变形长宽比分析
A Algorithm for Vision Location Based on Plane Quadrangle
一种基于平面四边形的视觉定位算法
a prismatoid whose bases are polygons having the same number of sides and whose other faces are trapezoids or parallelograms.
每个底部是边数相同的多面形且其它面是不等边四边形或平行四边形的旁面三角台。
[KJV] Every one had four faces apiece, and every one four wings; and the likeness of the hands of a man was under their wings.
四个基路伯各有四个脸孔，四个翅膀；在翅膀下面有人手的形状。
A Shape Optimization Research for Quadrilateral Mesh over the Triangular Surface;
三角网格曲面上四边形分割的形状优化研究