块隐式单步方法求解一类延迟微分代数方程

延迟微分代数方程(DDAEs)广泛应用于科学与工程各领域，但目前对这类问题的数值方法仅有很少量的研究．将块隐式单步方法应用于一类半显式指标1延迟微分代数方程，给出了方法的误差分析，理论分析和数值试验表明该方法对此类DDAEs的求解有良好的效果。     

利用谐波平衡法计算局部非线性动力系统的稳态响应

利用谐波平衡法研究了局部非线性系统在周期激励下的稳态响应问题。通过对系统的响应和非线性内力进行谐波分解将问题归结为一组非线性代数方程组。针对系统具有局部非线性的特点，对相应线性子结构的自由度进行减缩处理。采用Ｎｅｗｔｏｎ－Ｒａｐｈｓｏｎ迭代方法求解仅含非线性自由度的代数方程组。最后对算例进行计算，所得结果合理可靠。     

一类根式不可解代数方程

利用克罗内克定理给出了构造不可解代数方程的如下的一个充分条件：设整系娄ｎ次多项式ｆ（ｘ）在有理数域Ｑ上不可约,如果代数方程ｆ（ｘ）＝０的实根个数ｔ满足：１〈ｔ〈ｎ,则此代数方程不可根式求解。并且利用上述充分条件构造出一类根式不可解的代数方程－实系数ｎ次三项方程。     

结构动力响应灵敏度分析的Laplace变换法

提出了结构动力响应灵敏度分析的一种新方法－Ｌａｐｌａｃｅ变换法，该法对结构的微分方程和结构响应量灵敏度的微分方程分别进行了Ｌａｐｌａｃｅ变换，使其消去时间变量而转化成代数方程组。     

正交射流燃烧器气固两相流动的数值计算

运用气相ｋ－ε模型和颗粒相代数方程模型对正交射流煤粉燃烧器气固两相流场进行了数值模拟，获得了该燃烧器内的气、固两相速度分布，颗粒质量流分布，并与实验值进行了对比，两者定性符合，同时，探讨了颗粒直径对颗粒混合的影响，得到了一些很有价值的结论。     

可压缩可混溶驱动问题的共轭梯度迭代法的误差估计

有界区域上多孔介质中可压缩可混溶驱动问题由两个非线性抛物型方程藕合而成；压力方程和饱和度方程均是抛物型方程,对压力方程采用标准有限元方法，对饱和度方程用特征一有限元方法．对这两个方法离散后所得到的代数方程组，利用共轭梯度迭代法求解．通过详细的理论分析，给出了共轭梯度迭代解与原问题真解的最优阶H^1模误差估计．     

一类微分—代数系数实时控制的零阶保持算法

对于由微分－代数方程描述的一类系统，构造并研究了实时控制的零阶保持算法，为了对算法的控制误差进行补偿，提出了一个预估－校正格式，它可以将控制误差从O（h^3)改进到O（h^4)，得到的结果一般是最优的，作为例子，算法应用到耗尽关机射程控制系统的制导规律的设计，其控制精度可以达到O（h^3)或者O(h^4)。     

约束机械系统动力学的一类完全解耦方法

针对约束机械系统动力学分析所要处理的微分－代数方程组,先将其转化为基于隐式线性多步法的超定微分－代数方程组形式,然后采用一种微分流形的“投影”技术消除超定性,再对变化后的微分－代数方程组按照位置,速度,加速度的顺序进行解耦,化为线性方且的求解序列,从而得到一类完全解耦算法,算法可用于处理刚性问题,无需预估式,具有较高的效率,算例证明了该算法的有效性。     

三维非线性对流扩散问题多步Galerkin法及交替方向预处理迭代解

对三维非线性对流扩散问题构造了一种向后差分多步离散Ｇａｌｅｒｋｉｎ格式，并用交替方向预处理迭代法解多步Ｇａｌｅｒｋｉｎ法在每一时间步所产生的代数方程组。给出了迭代解的最优Ｌ＾２－模误差估计以及此方法的几乎是最优的工作量估计。     

一类非线性伪抛物型方程的D-R格式

针对一类非线性伪抛物型方程,构造了D-R格式,并给出了截断误差阶估计。该方法通过求解两个线性代数方程得到原问题的解,避免了非线性迭代运算,提高了计算效率。     

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.     

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     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with     

Journal of Donghua University ( English Edition) Contents of Volume 31

正~~     

Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has