四边形的

A quadrilateral distortion metric was proposed, which considered both of element minimal angle and warpage. An mesh smoothing approach of combining Laplacian method and μGA for quadrilateral mesh was presented, which could improve the mesh quality significantly without effect the algorithm's performance.

提出一种综合考虑单元最小角和翘曲的四边形网格质量评价标准，以该标准为优化目标，提出了一种以面积为权值的Laplacian方法与小种群遗传算法相结合的网格光顺方法，在兼顾计算效率的同时，可有效地优化网格形态质量。

This will be the first and last image to demonstrate what I am basically doing throughout the initial modeling process; I started out with a simple rectangular plane with symmetry mode on and I keep on extruding its edges and placing them in their rightful coordinates repeatedly until the entire structure is complete.

这会是第一张，也是最后一张图说明我在整个的建模过程中使用的基本技巧。我从一个开启了对称模式的简单四边形开始制作，不断地将边挤出，然后把它们放置到合适的位置，直到完成整个结构。

The study of crystal structure indicates that the complexes belongs to tetragonal,14(1)/a, a=b=27.047(5) A, c=14.103(3) A, a=b=y =90,V=10317(4)A3, Z=16, Dc=1.071g/cm3, F(000)=3408, R,=0.1395, R2=0.1766 and every unit of the tetranuclear complexes is four-coordinated to tridentate ligand and nitrogen atom in pyrazolone from other ligand. The complexes is slightly deformed square-planar geometry.

晶体结构研究表明，该配合物为四方晶系，空间群I4(1)/a，a=b=27.047(5)，c=14.103(3)，α=β=γ=90°，V=10317(4)，Z=16，Dc=1.071g/cm~3，F(000)=3408，R_1=0.1395，ωR_2=0.1766，其结构单元是由一个三齿配体中的ONO和另一个配体吡唑啉酮环二位上的N配位后形成略微畸变的平面四边形构型，其中Cu的配位数为4。

In order to remedy this kind of shortage, this paper presents a quick volume rendering method, for the finite element data field of dam seismic response, choices the slicing direction relying on the element surface which normal line has the smallest included angle with the view direction, slices elements to many quadrilaterals, blends the colors of these quadrilaterals by using OpenGL blending technology, and then superimposes all elements one by one.

为了弥补传统体绘制静止画面不能明确判断场值集中部位的不足，提出一种快速体绘制算法，针对大坝地震反应有限元计算数据场，根据每个单元法线与视线夹角最小的表面来选择剖切方向，将单元剖切成多个四边形面后，对单元的绘制顺序进行合理排序，利用OpenGL图形库函数进行颜色融合，再将各个单元依次叠加，从而生成了三维数据场的体绘制图。

The new machine can cut a taper with its top point fixed. The cutting motion of torch is realized by the composite revolving of the two orthogonal axes.

依据数学模型对机构的结构进行优化设计，机构采用平面的平行四边形机构，通过回转轴和连杆的转动合成割枪的切割运动。

By cooperating the two-model method with parallelogram frame in this paper, the curve of two crossed cylinders with their axises in a state of vertical can be easily and accurately realized, and the mechanism withdrawn from the method can be applied directly to the hole gas-cutting on high pressure capsules.

文摘：采用双靠模法与平行四边形机构的组合，可简易、准确地实现轴线垂直的两圆柱体相贯线轨迹的复现，其原理可直接用于压力容器上圆孔的气割。

The distances between inferior margin of 12th rib and the 3 above-mentioned nerves were all measured. Results: The superior lumbar triangle was quadrilateral (55%), triangular (35%) or irregular (5%). If the 12th rib was too short, the upper border of the triangle would be the 11th rib (5%). Four grouping patterns of the 3 nerves were found in front of the triangle, and the average distance between inferior margin of 12th rib and the 3 nerves was (16.92±6.32)mm,(59.49±14.97)mm and (112.49±17.15)mm, respectively.

结果：腰上三角的形态可为四边形(55%)、三角形(35%)和不规则形(10%)，该三角的上界可完全由第11肋(5%)构成；肋下神经、髂腹下神经和髂腹股沟神在腰上三角前方有4种不同的组合形式，三神经与第12肋下缘的平均距离分别为(16.92±6.32)mm、(59.49±14.97)mm、(112.49±17.15)mm。

The fast transmission of information is symbolized by the upward showing arrow formed by the two left parallelograms, the triangle formed by the third parallelogram stands for the strong and solid cooperation between the PCCW and SINOPEC.

标志中将三个平行四边形组成了一个向右和向上的箭头，来表达这一动态的传递，中间的正三角象征了企业间的合作坚实而稳固。

What we needed was (1) geometry based subdivision,(2) reasonable number of quadrilaterals, and (3) very low computational cost.

我们需要的是：（1）基与几何的再分，（2）合理的四边形数量，（3）非常低的计算成本。

For example, a cube is made up of six quadrilaterals where each vertex is shared by three polygons, but a different normal should be used for each of the three instances of each vertex, but a sphere is made up of many polygons where all vertices have common normals.

例如，一个立方体是由六个四边形组成，而每一个顶点被三个多边形共用，但是每一个顶点的三个实例应该使用不同的法向量，而由许多多边形组成的球，其所有顶点就有同样的法向量。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。