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1.
在AutoCAD中,在用户给定一个任意的放样截面、一个任意的放样路径曲线和一个任意放样比例曲线的情况下,截面在放样路径曲线上按放样比例曲线,变化截面大小,生成一个能进行布尔运算的管状Solid类型实体。  相似文献   

2.
在射影几何中,二次曲线定理告诉我们任意五点可以决定一条二次曲线.该曲线上其它点可以用巴斯加定理求出.但是巴斯加定理只能决定该曲线上各点的位置,而不能决定其类型.本文重点解决了任意五点决定的二次曲线的类型的判别.  相似文献   

3.
道路曲线的工程测量计算问题   总被引:1,自引:0,他引:1  
对道路工程测量中缓和曲线、圆曲线的计算问题进行研究 .讨论了缓和曲线及其等距线的数学性质、曲线点及曲线交点的大地坐标计算 ,以及编制VisualLISP程序对AutoCAD的二次开发 ,以解决理论的严格性和计算的实用性问题 .讨论的理论和方法均经过道路曲线测设的实例验证 .  相似文献   

4.
介绍了一种推导非对称基本型曲线的简单方法,并利用圆心点大地坐标,推导出非对称基本型曲线任意点的坐标计算公式.  相似文献   

5.
在AutoCAD中设计凸轮轮廓曲线通常比较繁锁,且绘图精度不高.将AutoCAD与Excel、Autolisp、C语言、MasterCAM等软件结合,能够快速而精确地生成凸轮轮廓曲线,极大地提高了设计精度和效率,并有效地保证了加工质量.  相似文献   

6.
根据测量不规则几何形状模具时误差的控制方法,提出了通过限制两型值点间拟合曲线段到两型值点间弦的最大距离来控制拟合精度的有理曲线拟合算法,并与Bezier曲线和参数三次Spline曲线进行了比较。  相似文献   

7.
依据四杆机构运动规律.进行数学分析,并建立数据模型,以此编写程序.用计算机对四杆机构曲线上的有关型质点的坐标进行准确计算,再以Parabola—fittingcurve(抛物调配曲线)理论为基础向各型质点之间插入新点,便能保证绘图仪输出的连杆上任意点的曲线光滑,且最大程度的接近真实的轨迹曲线.由于曲线图形是无穷的,可以在运行该CAD软件时,只需不断地改变a,b,c,d四杆长及输入连杆上或外侧点位置的有关数据,就能画出无数的曲线图,以构成完善的图谱,向设计者提供曲线图及其有关资料.  相似文献   

8.
为了实现大数据量曲线的自动化绘制,以差热-热重曲线为例,利用Excel软件对原始数据进行相应换算后,在AutoCAD软件内嵌的VBA程序编辑器中,编写了可自行读取Excel软件中数据并在AutoCAD绘图界面下自动绘制曲线的程序代码.当有多组平行实验数据时,通过该方法还可以实现曲线的批量化绘制.该方法操作简单,对数据适应性强,且源程序简单易懂,可为编程基础较差甚至零编程基础的大型分析仪器使用者提供参考.  相似文献   

9.
船体曲面的NURBS表达与设计   总被引:2,自引:0,他引:2  
在AutoCAD的ObjectARX开发环境中,以VC^ 为编程语言,建立了AutoCAD图形数据库与外部数据库的数据链接,采用非均匀有理B样条技术,对综合定型值点的船体曲面插值及边界条件处理进行了研究, 构造出以NURBS为统一数学表达式的船体曲面。根据投影原理,对船体曲面与任意平面的求交问题给出数值算法。首先用直线段逼近曲面的单参数曲线,在投影坐标系内求出直线段与平面的交点,再将交点映射到实际坐标系中得到真实的交点,这些点的集合即为平面与曲面的交线。  相似文献   

10.
介绍了任意设站极坐标法在公路、铁路施工阶段测设圆曲线、缓和曲线的原理和方法,并分别对圆曲线和缓和曲线上各点的坐标计算公式进行推导和讨论,给出了适合计算机编程的实用公式,该方法运用灵活,方便实用。  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

20.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

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