拟线性Volterra积分微分方程的hp-时间间断Galerkin方法

用hp-时间间断Galerkin方法讨论拟线性带弱奇异核的Volterra积分微分方程.利用线性化手段对原问题进行处理.证明了原问题和线性化问题是等价的,给出了有限元解的L2模误差估计.     

一般二维奇异问题的间断时空有限元方法

将时间允许间断而空间允许连续的间断时空有限元方法应用于一般二维奇异问题,给出解的存在唯一性证明,并给出加权索伯列夫空间模意义下的有限元解的误差估计,包括在允许的时间间断点tn处,有限元解产生跳跃时的误差.     

奇异半线性抛物方程的时空有限元方法

探讨研究了一类半线性抛物方程的自适应有限元方法,即时间间断、空间连续的间断时空有限元方法.把有限元方法和有限差分方法相结合,不对时空网格施加限制条件,证明了弱解的存在唯一性,给出了有限元解的时间最大模、空间加权L2模,即L∞(L2b)模误差估计.     

奇异线性抛物问题的时空有限元方法

讨论了一类奇异线性抛物方程的自适应有限元方法,即时间间断、空间连续的间断时空有限元方法.以对偶问题的强稳定性和误差估计为基础,给出了有限元解的加权L2模误差估计.     

对流占优微分积分方程的间断时空有限元法

采用Galerkin间断时空有限元法来处理对流占优微分积分方程，在时间离散区间内，利用Radau点处Lagrange插值多项式的特点，去掉间断时空有限元证明过程中对时空网格的限制条件，并给出了时间最大模、空间L2模。     

二维拟线性奇异抛物问题的时空间断有限元法

将时间允许间断而空间连续的时空有限元方法应用于二维拟线性奇异问题,利用线性化的方法,化为线性抛物方程予以处理,证明加权索伯列夫空间模意义下的有限元解的误差估计,包括在允许的时间间断点tn处,有限元解产生跳跃时的误差,最后再给出原方程的误差估计.     

Hp型间断有限元方法解奇异摄动Volterra积分微分方程

通过局部加密网格和提高分片多项式次数两种策略,用hp型间断有限元方法解奇异摄动Volterra积分微分方程.数值计算结果表明,hp型间断有限元解的数值通量在节点处具有与小参数无关的一致指数收敛性,而且hp型间断有限元解在L~2范数下具有一致指数收敛性.     

完备格上的拟-t-模及蕴涵算子的直积和直积分解

进一步讨论完备格上的拟t-模与剩余蕴涵算子,研究了它们的直积与直积分解,最终得到了直积分解的充要条件,解决了一个关于模与蕴涵算子的直积分解问题.     

解一阶双曲问题间断有限元方法的超收敛性质

研究求解一阶双曲问题的间断有限元方法并分析方法的稳定性和收敛性.对于k次间断有限元,利用对偶论证技术建立了在求解区域和某些子区域上的负模误差估计.利用负模误差估计进一步证明了间断有限元解在这些区域和它们的流出边界上均值逼近具有O(h2k+1/2)阶超收敛性质.数值实例验证了理论分析结果.     

四阶线性抛物型积分-微分方程的混合间断时空有限元法

利用混合有限元方法将高阶方程降阶，利用空间连续而时间允许间断的时空有限元方法离散方程，构造了四阶线性抛物型积分-微分方程的混合间断时空有限元格式．证明离散解的存在唯一性，稳定性和收敛性．     

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.     

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.     

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