几何基础
- 与 几何基础 相关的网络例句 [注:此内容来源于网络,仅供参考]
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With respect to syntax, the roles of tagmeme in the structure of word and sentence and Chomsky's Generative-Transformational Grammar are discussed. The spatial relation theory and existing research achievements are investigated. Having noticed the shortage of the capability of topological and metrical relation in the description of spatial information structure, the author proposes Combinational Qualitative Geometry based on the two invariables under ordinary transformations, distance ratio and direction difference, the CQG-based spatial relation system between topological and metrical constraint is thus constructed, on which several spatial relations such as parallel, perpendicularity, co-linearity, sequence and direct neighborhood are derived. Based on extended theory of spatial relation, the language anamorphosis is analyzed from the aspects of phonetics, semantics and syntax. The mere geometric and formalized spatial relation is then integrated with concrete geographic ontology to accommodate richer and indicative spatial configuration of spatial information in the different geographic context. Finally a syntax framework for spatial information is put forward.
在语法结构方面,首先阐述了法位和法素在语法结构词法和句法中的地位和作用,以及Chomsky生成转换语法的核心内容;详细介绍了地理信息系统空间关系理论及现有的研究成果;在分析现有的拓扑关系和量度关系对空间信息结构描述能力不足的基础上,提出了基于长度比和角度差两个不变量的组合定性几何,以此建立了介于拓扑及量度约束之间的组合定性关系体系,并以此为基础派生出平行、垂直、共线、次序、直接邻近等空间关系描述;本文基于扩展的空间关系理论,详细讨论了空间关系在语音、语法和语义三个方面的语言变体,将纯几何和纯形式化的空间关系与具体的地理本体结合起来,可以获得更为丰富的、更能反映空间关系在不同语言上下文中具体体现的组合关系;最后给出了一个空间信息的语法结构的基本框架。
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It provided a correct and reasonable mathematical model for the analysis of the ultimate bearing capacity and crankle stability of the thin-walled structure.
论文在比较了两种运动描述方法(完全拉格朗日法和更新拉格朗日法)异同点并分析了非线性几何关系及大变形下的弹性物理关系的基础上,基于增量虚功原理推导了几何非线性空间梁元单元切线刚度矩阵,采取分模块形式,分别表示了轴力、弯矩、双力矩对几何矩阵的贡献;通过球面显式荷载增量迭代式弧长法求解方法编制程序,很好地实现了几何非线性增量荷载的自动步长选择及全过程跟踪,为薄壁杆系结构的极限承载力分析和弯扭失稳分析,提供了较为精确合理的分析力学模型。
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This thesis contributes to geometry compression in the following aspects: Proposes a method of progressive spherical mesh parameterization based on local parameterization by directly projecting the deleted vertices to its neighborhood. Based on spherical mesh paramterization, an adaptive subdivision remeshing method by progressivly redistributing of sampling points is proposed, by this means, the main geometry information of the original mesh can be captured with only a small amount of samples, it can also be used in mesh simplification. By regarding attributes binded on mesh vertices as geometry signals and transferring them onto a uint sphere by means of spherical mesh parameterization, meshes with different attributes are compressed with spherical wavelet successfully with high compression rate. As a kind of lossy geometry compression technique, two mesh simplification algorthimes are also presented in this thesis.
归纳起来,本文的主要贡献有:提出了以直接投影局部参数化方法为基础的网格累进球面参数化方法;在网格球面参数化方法的基础之上,提出了一种基于累进优化布点方案的网格细分采样方法,该方法可以用很少的采样点就可以捕获到网格的主要特征,因此我们也将其用于后面的网格简化工作当中;通过将网格顶点上定义的各种属性看成几何信号,并以网格球面参数化为手段将几何信号迁移到单位球面上,从而成功地实现了用球面小波对各种几何信号的压缩;作为一种有损压缩方法,本文还提出了基于统一距离的网格简化算法和基于重采样的网格简化算法。
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The interpolate algorithms of three-order NURBS curve and double three-orders NURBS surface are presented. The expressions of partial derivative and normal curvature of NURBS surface are derived by the theory of differential geometry. The geometric characteristics of different curvature area of the free-form surfaces are analyzed in detail. All these work lays a theoretical foundation for constructing the cutter location calculating model of free-form surfaces NC machining. 2 On the basis of analyzing the methods of cutter path generation, the standard of evaluating the various methods of cutter path generation is presented. The method of generating cutter path with constant scallop height is presented for the first time.
本文以提高复杂曲面多坐标数控加工精度和加工效率为目的,在对国内外研究现状进行深入分析的基础上,对数控编程中各环节的关键技术问题进行了深入研究,主要内容包括以下几方面: 1 分析了复杂曲面各种造型方法的优缺点,给出了根据各种边界条件所确定自由曲面的NURBS表示方法以及三次NURBS曲线曲面反算算法;用微分几何理论推导了NURBS曲面的偏导矢及法曲率计算表达式;对曲面不同曲率特性区域的几何特征进行了深入分析,为建立复杂曲面的数控加工刀位计算模型奠定了理论基础。
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The questions covering pre-algebra and elementary algebra make up the Pre-Algebra/Elementary Algebra Sub score. The questions covering intermediate algebra and coordinate geometry make up the Intermediate Algebra/Coordinate Geometry sub score. The questions covering plane geometry and trigonometry make up the Plane Geometry/Trigonometry sub score.
包含有基础初等代数和初等代数的考题构成了基础初等代数/初等代数的技能分数,涉及到中等代数和坐标几何的考题构成了中等代数/坐标几何的技能分数,而涵盖平面几何和三角函数的考题则构成了平面几何/三角函数的技能分数。
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The main jobs of this paper are as followed: 1 The reuse of the frame design technology for aircraft assembly fixtures is researched. a frame line part library is built with the templet driven technology, the reuse of the frame line part come true by the tools for instantiation and instance modification. The design resources are effectively used, some repeating work is cut. 2 Two methods to obtain the assembly feature are proposed: the straight way by the Enumeration method and the indirect way by project features to the assembly plane. All of the assembly features of the frame and the adjustable bearings are obtained by these two methods which makes the frame automatic assembly technology for aircraft assembly fixtures come true. 3 The frame automatic assembly technology aircraft assembly fixtures based on assembly features is researched. A binary tree assembly model is used to express the assembly information of the frame for aircraft assembly fixtures, the automatic assembly between the frame, the aircraft and the adjustable bearing is completed within the three steps: distribute, obtain and evaluate assembly feature. Finally, the efficiency of the frame assembly design is proved. 4The frame interpart modeling technology for aircraft assembly fixtures is researched, the intersection methods are concluded and the arithmetic of the single-cut, double-cut and inter-cut intersection is proposed, the interpart fast modeling of the frame design for aircraft assembly fixture come true. 5Based on the researches mentioned before, a sub-system of frame fast design for aircraft assembly fixture is developed on CATIA. The sub-system is used to design the aircraft assembly fixtures in a large aeronautics corporation and make a good- effect.
论文的主要工作如下: 1研究了飞机装配型架骨架设计重用技术,在总结归纳骨架线框结构类型的基础上,应用模板驱动的方法建立了骨架线框库,通过骨架线框零件的实例化和离线编辑实现骨架线框的重用,有效利用设计资源,减少重复劳动; 2提出穷举几何对象的装配特征直接获取方法,遍历零件模型的几何对象,从中捕捉所需装配特征,该方法简捷、高效;提出向装配面投影的装配特征间接获取方法,该方法在现有特征基础上生成装配特征,解决了部分装配特征难以直接获取的问题; 3研究了基于装配特征的飞机装配型架骨架自动装配技术,采用一种二叉树装配模型表达骨架的装配关系,并通过装配特征的分配、获取和赋值三个步骤,实现了骨架分别与飞机产品和可调支承的自动装配,避免了繁琐的人工交互操作,提高了骨架设计的效率和规范化程度; 4研究了飞机装配型架骨架零件间建模技术,在总结归纳骨架元件相贯处理方式的基础上,提出了骨架元件单剪切相贯、双剪切相贯和互剪切相贯的实现算法,简化了骨架相贯处理的过程; 5基于以上研究,在CATIA平台上开发了飞机装配型架骨架快速设计子系统,并应用于某大型航空企业的装配型架设计,提高了设计效率和设计质量。
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The nonlinear optical properties of one-dimension nonsymmetrical D-π-A charge-transfer molecule VPDB in gas phase and different solvents have been studied on the base of time dependent density functional theory.
首先在密度泛函理论基础上优化了气相下该分子体系的几何结构;考虑溶剂效应时采用了极化连续模型,在密度泛函理论基础上采用极化连续模型优化了分子在不同溶剂中的几何结构。
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The main results are as follows:(1) In Chapter 2, the proof of the main theorem on quadratically related m-geometric sequences in [5] is simplified and consummated; A family of GMW-geometric sequences derived from GMW sequences are constructed, and their correlation functions and linear complexities are given.
本文也正是从扩频码序列的相关性能和安全性的角度来构造和研究了几类扩频码序列集合,得到以下的结论:(1)第二章首先简化并且完善了文献[5]中关于二次相关m-几何序列的主要定理;其次,在GMW序列的基础上构造了GMW-几何序列,计算了GMW-几何序列的相关函数;最后给出了GMW-几何序列的线性复杂度。
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In general, the major results are:(1) Established the geometrical model for the enwinding of the wire rope in the roller, such as the inclination of the wire rope and the climbing equation of roller in the commutation process;(2) Established the tensile force kinetic model for the enwinding wire rope used the Lagrange kinetic equation and the continual kinetic theory in the start up and retard moment. Solved the equations by the method of modal analysis and separation of variables(3) Based on the analysis on the enwinding mechanism of the wire rope, we did the research on the mechanics behavior of the wire ropes enwinding process.(4) According to the research above, we made the computer program to solve the mechanics models. And after parametric analysis, we made the suggestion for the improving of the current wire rope enwinding system.
主要研究工作有:(1)建立了钢丝绳在滚筒缠绕几何模型,研究了钢丝绳缠绕过程极限偏角及换向过程在滚筒爬坡机理及几何模型;(2)依据LAGRANGE系统广义动力学方程、连续体动力学理论分别建立起升系统启动及制动过程钢丝绳缠绕快绳拉力的动力学模型,并分别采用模态分析法及分离变量法求解;(3)结合对钢丝绳在钻机滚筒缠绕机理分析的基础上,研究了钢丝绳在滚筒缠绕过程力学行为;(4)编制计算机仿真程序对上述模型进行求解,在参数分析的基础上提出对目前钢丝绳缠绕系统结构改进建议。
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Rresults from those studies can be summariazed as follow:(1) A preliminary study no correlationship between the UV-VIS reflection spectrum of tomato fruit surface and the lycopene amount of tomato fruit was undertaken. Based on observation from this study, a damage-free and in-situ detection technique of lycopene amount from tomato was developed with UV-VIS reflection spectroscopy;(2) The geometrical isomers of lycopene were separated successfully on C30-HPLC-PDA-ELSD. The absorption coefficients of Z-isomers were consequently dedermined. The geometrical isomer composition of lycopene could therefore be assessed. Those efforts formed a solid base to identify the natural product from synthetic compound of lycopene;(3) Lycopene resource from the fruit of Autumn oliver was proved to be available for industrial application. An extraction methos of lycopene from the fruit of Autumn oliver by supercritical carbon dioxide was developed at laboratory scale;(4) A method to extract lycopene by supercritical liquid with improved efficiency was developed; Data from this investigation suggested that a proper raw material pre-extraction process was important for a better extraction efficiency;(5) Variation in the geometrical isomer composition of lycopene during its metabolish in rat was assessed. A large amount of Z-isomers were observed. This variation took place in serum;(6) The absorption rate and accumulation in serum of natural lycopene in rat were assessed;(7) Ability to quench singlet oxygen by different geometrical isomers of lycopene was compared;(8) It was detected that whether natural lycopene had functions to regule blood-lipids and LDL antioxidation;(9) A C31 degradation piece of lycopene was found in the prostate gland of rat.
研究结果包括:[1]应用UV-VIS反射光谱法建立了番茄果实中番茄红素含量的无损伤、现场检测技术;[2]应用C30-HPLC-PDA-ELSD技术实现了对番茄红素几何异构体的分离,测定了不同顺式异构体的吸光系数,建立了天然番茄红素几何异构体组成的检测方法,为区分和鉴定人工合成品和天然产物奠定了基础;[3]证实了秋橄榄果实中的番茄红素资源具有工业开发价值,并建立了超临界CO_2萃取的实验室方法;[4]探索了提高番茄红素超临界流体萃取效率的方法,证明了物料前处理对提高萃取效率起了极其重要的作用;[5]观察了番茄红素在大鼠体内几何异构体组成的变化情况,发现了大量顺式异构体的存在,并证实了几何异构体组成在血清中发生了显著变化;[6]测定了天然番茄红素在大鼠体内的吸收率和在大鼠血清中的动态积累规律;[7]比较了不同番茄红素几何异构体淬灭单线态氧的能力;[8]检测了天然番茄红素是否具有调节血脂作用和抗低密度脂蛋白氧化的功能;[9]首次发现大鼠前列腺内存在番茄红素C31降解片段,并证实其仍具有淬灭单线态氧的能力。
- 推荐网络例句
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Lugalbanda was a god and shepherd king of Uruk where he was worshipped for over a thousand years.
Lugalbanda 是神和被崇拜了一千年多 Uruk古埃及喜克索王朝国王。
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I am coming just now,' and went on perfuming himself with Hunut, then he came and sat.
我来只是现在,'歼灭战perfuming自己与胡努特,那麼,他来到和SAT 。
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The shamrock is the symbol of Ireland and of St.
三叶草是爱尔兰和圣特里克节的标志同时它的寓意是带来幸运。3片心形叶子围绕着一根断茎,深绿色。