四边形

Behind him to the west, Langdon knew the ancient obelisk of Ramses rose above the trees, marking the Musée du Jeu de Paume.

轿车沿着一个环形池塘在奔驰，穿过了一条废弃的大道驶进远处的一块四边形场地。

Three-dimensional reconstruction is realized by three-dimensional morphological characteristic of cucumber leaf ,cubic Bezier curve of leafstalk,pentagon leafstalk section,jointing quadrangle leafstalk surface,leafstalk shags built by random and joint sequential C0 cubic NURBS surface in cucumber.

根据黄瓜叶的三维形态特征，利用3次Bezier曲线描述黄瓜叶柄曲线，采用五边形作为叶柄截面，用四边形面片进行叶柄表面拼接，并用随机方法生成叶柄的粗毛；利用C0连续的3次NURBS曲面拼接生成了黄瓜叶片曲面，实现了黄瓜叶的三维重建。

A map projection in which quadrilaterals formed by meridians and parallels have an area on the map proportional to their area on the globe.

由子午线形成四边形并且把地球上的领域相应的投射在地图上形成的地图投影图。

"A great many people and a great number of circumstances in my old schools crossed each other so as to make up of a resultant force like countless parallelogram in mechanics principle, which directs our outlook on life and value; it is these certain expressions and unforgettable details of some familiar people that are borne in mind memorably, which has formed the four-year history."

"是母校中的许许多多人和事，相互交叉形成合力，像无数个力学原理中的平行四边形，引导了我们的人生观、价值观；正是这些熟悉的人的某些表情和难忘的小细节仍留在记忆深处，才构成了这四年的历史。"

To establish the constitutive equation of material, the metric tensor for stress , strain and their transformation equations between different configurations are derived, and basic theory of finite deformation as well as elasto-plastic deformation criterion are studied. By analyzing the applicability of different element models, four-node quadrilateral degenerated Mindlin isoparametric element is adopted because of its good versatility, and the element stiffness matrix is derived. The static implicit elasto-plastic finite element equation for complex skin stretch-forming is put forward based on Updated Langrange formulation.

本文首先系统地阐述了有限变形的相关基本理论，针对板料成形建立了应力应变度量张量及其相应的转换关系；介绍了材料的屈服准则、塑性变形强化规律、塑性流动规律以及加、卸载准则，并在此基础上建立了有限变形各向异性弹塑性本构方程；对板料成形的单元模型进行了分析，针对飞机蒙皮零件特点，采用通用性强的四节点四边形退化Mindlin等参壳单元进行成形模拟，并导出其单元刚度矩阵的具体形式；基于以上研究，以逐级更新Langrange描述的持续虚功率原理为基础，建立了率形式的复杂蒙皮拉形过程静态隐式弹塑性有限元方程。

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。

A two - mast ed sailing ship,square - rigged on both mast s,carrying two or more headsails and a quadrilateral gaff sail or spanker aft of the mizzen mast .

双桅横帆船有两根桅杆的帆船，每个桅杆上都有横帆，载有两个或更多的前帆和一个四边形的斜桁帆或在后桅的尾部装有后樯纵帆

A two-masted sailing ship, square-rigged on both masts, carrying two or more headsails and a quadrilateral gaff sail or spanker aft of the mizzenmast.

有两根桅杆的帆船，每个桅杆上都有横帆，载有两个或更多的前帆和一个四边形的斜桁帆或在后桅的尾部装有后樯纵帆

We mainly give a simple brief introduction to Morse theory and Morse function, and introduce a two-dimensional manifolds on the Morse-Smale complex.

在此基础上，提出了一种对二维流形上的Morse-Smale复形顶点进行优化从而达到优化四边形形状的算法。

Called Oporto Vodafone Building, the project has a faceted concrete shell with angular windows.

波尔图沃达丰建筑的外表皮由四边形的面板与三角形玻璃窗构成。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。