有限空间年龄结构种群模型一个新的间断Galerkin方法

本文对有限空间年龄结构种群模型提出了一种新的数值方法,通过将标准的间断Galcrkin有限元法与流线扩散有限元法相结合,建立了一个稳定的间断有限元格式,并讨论了格式解的收敛性.     

Sobolev方程的经济型差分-流线扩散法

根据Sobolev方程的特点,采用了经济型差分-流线扩散法研究了其初边值问题,建立其EFDSD格式,分析了该方法的稳定性和收敛性,并得到了H1-模误差估计.     

两项时间分数阶扩散方程的一种数值解法

扩散方程在物理领域常用来模拟不同物质间的相互扩散现象,多项时间分数阶扩散方程能更清晰地反应复杂系统的物理意义.本文对两项时间分数阶扩散方程中的分数阶导数直接进行离散,空间导数采用中心差分格式进行离散,提出了求解两项时间分数阶扩散方程的一个隐式差分格式;讨论了分数阶扩散方程差分解的存在唯一性,证明了差分格式的稳定性及收敛性;最后数值试验验证了格式的有效性.     

求解扩散方程的Pade′逼近方法

对扩散方程提出了精度为O(t3+h2)的差分格式,首先对空间变量中心差分格式离散,所得到常微分方程组利用指数函数的Pade[2/1]逼近,得到空间二阶时间三阶精度的两层绝对稳定的隐式差分格式,并讨论了稳定性.数值结果与Crank-Nicholson格式进行比较,数值结果表明,该格式不但有效地解决初始边界条件间断问题,而且适合于大时间步长问题.     

输运方程谱有限元耦合方法 及其在核工业中的应用

本文研究求解Boltzmann方程的谱有限元耦合方法,给出了求解输运方程的谱标准Galerkin有限元、谱流线扩散有限元、谱间断有限元耦合格式.研究这些格式的收敛性,并将它们应用到了核测井领域.     

输运方程谱有限元耦合方法及其在核工业中的应用

本文研究求解Boltzmann方程的谱有限元耦合方法,给出了求解输运方程的谱标准Galerkin有限元、谱流线扩散有限元、谱间断有限元耦合格式.研究这些格式的收敛性,并将它们应用到了核测井领域     

方柱绕流的大涡模拟

采用物理分步法对方柱绕流的流动分离现象进行了大涡模拟(LES).物理分步法将N-S方程剖分为对流、扩散及波动过程,对不同的物理过程分别采用适宜的方法进行求解.对流过程采用逆风——中心差分格式求解;扩散过程采用中心差分格式求解;压力方程采用SOR迭代法求解.计算的方柱四周的平均压力系数的分布与物理模型试验结果吻合良好;模拟的流动现象也得到了物理模型试验的证实.     

求解二维扩散方程的一种高精度紧致差分格式

扩散方程通常用来描述扩散现象中的物质密度的变化或者与扩散相类似的现象,针对二维扩散方程提出了一种高精度紧致差分格式,该格式基于四次样条函数对空间变量进行离散,对时间导数采用(2,2)Padé逼近,从而得到了时间和空间均为四阶精度的紧致差分格式.然后证明了该格式是无条件稳定的.最后通过数值实验,验证方法的精确性和稳定性.     

求解流线曲率法反命题的一种新型有限差分方法

针对全三元离心叶轮流线曲率法反命题设计,提出了一种求解S2m流面速度梯度方程的新型有限差分解法。该方法将相对速度沿准正交线的方向导数采用前向差分格式,将相对速度沿流线的方向导数分解为两项,一项采用前向差分,另一项采用后向差分格式,其他各参量沿准正交线或流线的方向导数统一采用前向差分格式。这样便解决了简单采用前向差分格式或后向差分格式难以保证求解速度场的矩阵主对角线元素占优问题,使求解格式具有较强的稳定性和收敛性。新型有限差分求解方法应用于Krain叶轮的改型设计,经计算流体动力学(CFD)分析得,改型叶轮效率提高约0.3%,压比提高约0.2,表明利用新型有限差分法求解S2m流面速度梯度方程是可行的。     

一种计算激波的守恒差分格式

介绍了一种处理激波间断解的差分格式,此格式是基于在间断解的两侧使用不同计算公式的守恒差分格式;证明了该格式满足离散熵条件。     

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.     

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.     

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.     

A computer generator for randomly layered structures

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

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.     

海南岛地体及其毗邻陆缘晚中生代—新生代古地磁研究和构造演化

本文叙述了对海南岛及其毗邻大陆边缘白垩纪到第四纪地层岩石进行古地磁研究的全部工作过程。通过分析岩石中剩余磁矢量的磁偏角及磁倾角的变化,提出海南岛白垩纪以来经历的构造演化模式如下:早期伴随顺时针旋转而向南迁移,后期伴随逆时针转动并向北运移。联系该地区及邻区的地质、地球物理资料,对海南岛上述的构造地体运动提出以下认识:北部湾内早期有一拉张作用,主要是该作用使湾内地壳显著伸长减薄,形成北部湾盆地。从而导致了海南岛的早期构造运动,而海南岛后期的构造运动则主要是受南海海底扩张的影响。海南地体运动规律的阐明对于了解北部湾油气盆地的形成演化有重要的理论和实际意义。     

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.     

《Chinese Science Bulletin》SUBJECT INDEX TO VOLUME 59(2014)

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Achieving Unusual States of Matter Under High Pressure

The elongation method,originally proposed by Imamura was further developed for many years in our group.As a method towards O(N)with high efficiency and high accuracy for any dimensional systems.This treatment designed for one-dimensional(ID)polymers is now available for three-dimensional(3D)systems,but geometry optimization is now possible only for 1D-systems.As an approach toward post-Hartree-Fock,it was also extended to