对流占优扩散方程的一种基于斜线性插值的特征差分算法

将特征线法和有限差分法相结合，借助于斜线性插值。给出了求解对流占优扩散方程数值解的一种新的特征差分格式。并研究了算法的收敛性。该算法的优点是特别适用于求解变系数的对流占优扩散方程。能更有效地消除数值振荡现象。     

非线性对流占优扩散方程的一种基于斜线性插值的特征差分算法

目的建立既简单,稳定性又好的求解非线性对流扩散方程的数值算法。方法采用斜线性插值,将特征线法和有限差分法相结合。结果给出了一种基于斜线性插值的特征差分格式。结论该算法适用于求解变系数的对流占优扩散方程,能更有效地消除数值震荡现象     

一维非线性对流扩散方程特征有限元的两重网格算法

针对一维非线性对流扩散方程，构造了特征有限元两重网格算法。该算法只需要在粗网格上进行非线性迭代运算，而在所需要求解的细网格上进行一次线性运算即可。对于非线性对流占优扩散方程，不仅可以消除因对流占优项引起的数值振荡现象，更重要的是可以加快收敛速度、提高计算效率。误差估计表明，只要选取粗网格步长与细网格步长的平方根同阶，就可以使两重网格解与有限元解保持同样的计算精度。     

对流占优扩散问题的一种特征差分方法

用基于一般的 L agrange插值的特征差分方法求解对流占优扩散问题 ,会出现较大的数值扩散或者数值振荡等困难 ,高阶单调插值又计算复杂。该文采用 A.A .Sam arskii构造差分格式的方法 ,建立了一种新的特征差分方法。先对对流扩散方程的扩散项进行修改 ,然后再进行特征差分。此方法具有较高精度 ,并消除了非物理振荡。证明了方法的无条件稳定性。数值结果表明 ,该方法可成功求解对流占优扩散问题。     

二维非线性对流扩散方程特征有限元方法

应用特征有限元Galerkin方法,研究对流占优的二维非线性对流-扩散方程的数值求解问题。建立了非线性对流-扩散方程的特征有限元Galerkin形式,给出了特征有限元法的最优阶误差估计。误差分析及数值结果表明,该方法具有较好的收敛性与稳定性,并且克服了用有限元或差分法经常出现的数值振荡现象。     

一类对流占优奇异系数多孔介质方程的局部间断有限元方法研究

本文研究求解一类对流占优奇异系数多孔介质方程的局部间断有限元方法,给出了处理方程奇异系数的方法和详细的局部间断有限元格式。该方法通过适当改写原方程并引入对流流通量以及扩散流通量,可以有效地抑制传统有限元方法求解对流占优问题在大梯度区域出现的数值伪震荡。数值实验表明该方法能有效求解对流占优奇异系数多孔介质方程。     

对流扩散方程的二次单调插值特征差分方法

特征差分方法适合于求解对流占优扩散问题,但也存在着精度低或非物理振荡等缺点.为克服其不足,建立和研究了二次单调插值特征差分方法.此方法具有较高精度并消除了非物理振荡.方法是无条件稳定的.用交替分组显式(AGE)方法求解了差分方程,方法便于并行计算.数值结果表明,方法可成功地求解对流占优扩散问题.     

二维线性对流扩散方程一种新的特征差分算法及收敛分析

文章讨论了二维线性对流扩散方程,将特征线法和有限差分法相结合,借助于双线性插值,给出了求解二维线性对流扩散方程数值解的一种新的特征差分格式,并分析了该算法的收敛性。此算法表明对于一类对流扩散方程,应用此差分格式,能更有效地消除数值振荡现象,从而极大地提高数值逼近度。     

二维线性对流扩散方程一种新的特征差分算法及收敛分析

讨论了二维线性对流扩散方程,将特征线法和有限差分法相结合,借助于双线性插值,给出了求解二维线性对流扩散方程数值解的一种新的特征差分格式,并分析了该算法的收敛性.此算法表明对于一类对流扩散方程,应用此差分格式,能更有效地消除数值振荡现象,从而极大地提高数值逼近度.     

对流占优对流扩散方程的间断有限元(DG)解法

对于对流占优的对流扩散方程,采用一种间断有限元(DG)方法进行了数值求解.采用了一种p-谱系基函数,研究了L2模误差的数值行为.     

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-