一种多张裁剪曲面的三角化算法

针对多张裁剪曲面的三角化问题,提出一种多张裁剪曲面三角剖分算法．该算法在进行多张裁剪曲面的三角化时,首先采用匹配的方法离散各曲面的边界,再对各曲面进行三角化,因而能有效地防止曲面相交处的三角化结果出现裂缝,孔洞和覆盖等现象．提高了多张裁剪曲面三角化算法的正确性．该算法已经成功应用于“超人ＣＡＤ／ＣＡＭ”曲面造型及加工系统,主要用于快速原型技术（ＲＰＴ） 的ＳＴＬ文件生成,算法表现稳定．     

三角域上的有理Lagrange插值曲面及其求值递推公式

三角域上的曲面造型技术以其适应于不规则与散乱数据点的几何造型和避免出现退化等特性而广受重视．文章给出了三角域上有理Ｌａｇｒａｎｇｅ 插值曲面的定义和求值的递推公式．     

补白

三角域上的曲面造型技术以其适应于不规则与散乱数据点的几何造型和避免出现退化等特性而广受重视.文章给出了三角域上有理Lagrange插值曲面的定义和求值的递推公式．     

插值Loop曲面细分算法在堆焊自由曲面重建中的应用

针对堆焊自由曲面焊缝形貌不规则致使焊缝识别精度低、自动焊接困难的问题,提出了一种利用插值Loop曲面细分算法对旋转电弧传感器采集的堆焊焊缝三维形貌数据进行曲面重建的方法。首先,采用格拉布斯(Grubbs)检验算法对异常采样点进行滤波处理,得到质量较高的形貌数据;然后,采用局部最优Delaunay算法对形貌数据进行初始三角网格剖分;最后,利用插值Loop曲面细分算法对初始三角网格进行曲面细分,实现焊缝三维形貌重建。结果表明,此方法的曲面重建效果良好,降低了初始三角网格剖分的误差,实用性强。     

基于点数据集三维空间曲面三角化算法实现

在地质、医学等科学研究领域中,基于原始数据建立三维空间图像模型的研究具有较高价值;特别在三维地质构造建模中,测量获取的原始数据采用点数据集形式表示。基于点数据构建三维空间曲面三角化网格模型能够很好地还原点数据集所表示的曲面形态和展布,在现有的三角化剖分算法研究的基础上,提出一种基于点数据集三维空间曲面三角化网格模型生成算法;该算法生成的网格模型质量较高,能够较好地描述点集所表示的曲面形态。采用描述地质界面的点数据集进行算法验证与测试,根据边界数据实际情况,生成三维空间曲面三角化模型并更新网格模型边界,效果比较理想。     

采用R*-tree的三角网格曲面非均匀精简算法

提出了一种三角网格曲面非均匀精简算法.该算法采用R*-tree组织三角网格曲面的空间拓扑结构,实现了三角面片拓扑邻域的快速查询.结合三角网格曲面模型的曲率分布状况,对三角网格曲面进行聚类分簇处理,通过对分簇网格进行局部精简,实现了三角网格曲面模型的整体保形性精简.与同类精简算法的对比实验表明,该算法的数据适应性强,有效地保留了三角网格曲面的型面特征,精简后的网格模型与原网格模型的面片偏差降低了20%～45%,精简时间减少了10%～35%.     

基于能量法的曲面节点整体插入算法

提出了一种基于逼近与插值相结合的曲面构造法。阐述了一种基于能量法的曲面节点整体插入算法，将它运用于初始曲面的构造，并在自开开发的面向数据控加工的曲面造型系统中实现。实践表明，这种算法能够一次性求出曲面上的所有未知节点，并使曲面具有较好的光顺性能。     

基于逼近体积最小准则的最佳三角剖分研究

研究工程中大量散乱数据的三角剖分 ,提出了基于逼近曲面体积误差最小的最佳三角剖分准则 ,为了快速得到满足此准则的三角剖分 ,给出了启发式搜索算法和该算法在实际曲面重构应用中的一个实例 .结果表明 :重构的结果较好 ,且三角剖分的拓扑保持一致     

细分曲面造型中的框架级布尔运算

提出一种对实体初始三角网格进行操作的布尔运算，称之为框架级布尔运算．通过该运算可以构造出一个新实体的初始网格，然后采用Loop细分算法完成该实体的光滑曲面造型．在初始三角网格的求交过程中使用注册机制对所得交点的拓扑约束关系进行分类推理，从而对浮点数值容差导致的失误进行了有效控制和纠错．     

基于海量散乱数据的数据压缩及曲面重建新方法

基于三维散乱数据的曲面重构是反向工程中的一项关键技术.文章针对大规模的散乱数据点,给出了一种数据压缩及生成曲面三角网格的新算法.该算法首先按照压缩比例在原始点中提取定量的分布均匀的点作为压缩后的点,然后利用原始点和压缩后的点之间的关系构建三角网格.最后再进行拓扑修正及网格优化,从而得到拓扑正确且均匀的三角网格曲面.实验表明,该算法简单,易于操作,具有较强的适用性.     

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.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

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.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

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-