应用Casteljau算法绘制Bezier曲面

Casteljau算法是一种运用递归方法求得Bezier曲线上点的算法。针对任意次Bezier曲面的绘制需求,提出一种应用Casteljau算法绘制Bezier曲面的方法,避免了矩阵运算绘制高次Bezier曲面效率低的局限性。实验表明这种方法可行,且效率高。     

动态绘制任意阶Bezier曲线的算法及其实现方法

介绍了如何利用VC 编程技术在图形系统中动态绘制任意阶Bezier工程曲线方法，并且使绘制的曲线具有捕捉、修改、动态增加型值点等功能。利用同样的方法，可以实现B样条、三次参数等其它工程曲线的绘制，从而扩大了Bezier等曲线的工程应用。     

基于有理二次Bezier曲线的G2连续的插值曲线

给出有理二次Bezier曲线G^2连续的条件，通过对条件中权因子的调整，构造一条能过所有控制点G^2连续的插值曲线．在此曲线的绘制中使用了一种快速逐点生成算法，该算法只用到加减法，较大的提高了效率．     

VC中任意方向椭圆的生成算法及其程序设计

本文通过对Bezier曲线的生成原理的描述，说明了在VC中绘制任意方向椭圆的方法，并给出了部分实现代码．     

两相邻Bezier曲线近似合并的一种方法

从两Bezier曲线间的最小二乘范数下的距离函数中取最小值，利用Bezier曲线细分后的矩阵表示，给出了把两相邻n次Bezier曲线合并成一条n次Bezier曲线的一种方法，得到了用矩阵表示的合并曲线的控制顶点的显示表达式．在合并过程中，分别讨论带左右端点任意阶插值条件和不带左右端点插值条件的合并；若先对原曲线进行升阶，然后对升阶后的曲线进行合并，则可减小合并误差．数值实例显示，用此方法所确定的合并曲线对原曲线有较好的逼近效果．     

一种能量高效的无线传感器网络等值线监测技术

针对无线传感器网络环境监测应用中的能量受限问题,提出一种基于Bezier曲线的无线传感器网络等值线监测方法——SENS-T.利用等值线来表示环境监测值的分布信息,即将等值线划分为若干Bezier曲线段,每条曲线段的信息由一个代表节点负责传回汇聚中心,汇聚中心再根据网络节点坐标与接收的曲线信息进行等值线还原.汇聚节点的数量由划分的Bezier曲线段的段数决定,从而改良了传统方法中等值线上所有节点都要进行汇聚的做法.仿真表明,SENS-T可有效节省网络能量和带宽,与传统等值线监测方案相比,在达到相同等值线绘制精度的同时,可节省约45%的网络能量.     

正则Bezier曲线的广义偏距曲线及其Matlab实现

利用deCasteljau算法求得正则Bezier曲线上各点处的切矢，由此得到x轴到Bezier曲线P（u）上各个点处的切向量的角θ（u），应用于求原始正则Bezier曲线的广义偏距曲线．该方法几何意义明显，算法简洁．同时给出了用Matlab绘制Bezier曲线及其广义偏距曲线的程序，并给出了实例．实践表明，该方法准确快捷，效果较好．     

Bézier曲线的算子表示

Bezier曲线是计算机辅助几何设计(CAGD)领域中广泛运用的一种曲线。首先引入三个基本算子:移位算子、恒等算子和向前差分算子,然后将Bernstein-Bezier形式的Bezier曲线表示为更为简洁和直观的算子表示形式,并进一步讨论算子表示下Bezier曲线的各种性质,给出相关证明过程。实践表明,算子表示形式从与传统表示方法不同的另一角度揭示了Bezier曲线基本几何性质,简化了相关结论的推导。     

一种在MDT环境中应用Bezier曲线进行曲线调整的方法

在详细分析用Bezier曲线表述圆弧段曲线的基础上,提出采用Bezier曲线并结合MFC以及ARX等二次开发工具在MDT环境中实现曲线调整的方法,并给出了详细的实现思路和过程。实际开发经验表明,该方法是一种使用方便的人机交互式的动态优化方法,具有较高的实用价值。     

C—Bezier曲线

讨论了C—Bezier曲线的端点特性和曲线的性质，给出了C—Bezier曲线和Bezier曲线的G^1光滑拼接和G^2光滑拼接的几何条件，并利用C—Bezier曲线精确地表示二次曲线．     

Markedness and its Interpretation in Language Use

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.     

Features of Women's language

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

低渗透非均质砂岩油藏启动压力梯度研究

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。     

On Tragic Consciousness In The Works By Ernest Hemingway

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.     

Achieving Unusual States of Matter Under High Pressure

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-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

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-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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