污染环境中n维食物链模型研究

本文对环境容量很大且被污染情况下的多种群食物链群落模型进行了研究。得到了食物链中各种群平均持续生存与绝灭的充分条件,并得到了保证各种群持续生存对外界输入毒素率的控制条件。     

一个带时滞的离散模型的一致持续生存

研究了一个带有有限多个时滞的Lotka-Volterra离散模型.以持续生存函数为基础,通过定性分析方法,得到了种群一致持续生存和绝灭的条件.结果表明,该模型与其相平行的连续模型有着相同的持续生存条件.     

带营养再循环项的双营养竞争恒化器模型分析

构建了营养再循环情形下的两微生物种群竞争利用双营养的恒化器模型，得到了微生物种群绝灭和一致持续生存的充分条件。     

污染环境中具有阶段结构的种群模型的生存分析

研究了污染环境对具有阶段结构的种群模型的影响,考虑到新生个体的出生对种群体内毒素的影响,以及死亡的种群个体将毒素带回环境.主要运用比较定理,给出了种群一致持续生存,弱持续生存和绝灭的判据.     

污染环境中具有阶段结构的种群模型的生存分析

研究了污染环境对具有阶段结构的种群模型的影响,考虑到新生个体的出生对种群体内毒素的影响,以及死亡的种群个体将毒素带回环境。主要运用比较定理,给出了种群一致持续生存,弱持续生存和绝灭的判据。     

污染的恒化器中食饵与捕食者的持续生存

本文研究了污染的恒化器中,食饵与捕食者的持续生存,分别得到了食饵与捕食者种群持续生存与绝灭的阈值,及两种群共存的一个充分条件。     

一类三种群混合扩散模型的持续生存

本文对一类三种群混合扩散模型进行研究，得到了扩散对系统持续生存影响的充分条件，表明即使食饵种群在某些孤立斑块中可能绝灭，也可以通过适当选取扩散率来保证系统持续生存。     

双营养Chemostat模型的渐近性态

研究了含有时滞的双营养chemostat模型的渐近性态.首先利用泛函微分方程的单调理论分析了单种群chemostat模型正平衡点的全局渐近稳定性.对于两种群chemostat模型,利用无限维动力系统的理论给出了该系统一致持续生存的充分条件.     

一类捕食chemostat模型的食饵一致持续生存

考虑了一类双营养条件下带时滞的捕食chemostat模型。利用Liapunov泛函方法和Razumikhin方法,得到了食饵种群的一致持续生存,而捕食者种群趋于绝灭的充分条件。     

二维时变Volterra互惠系统的生存分析

采用积分均值和微分不等式方法，研究了二维时变Voherra互惠系统的生存状况．在种群体内毒素浓度不同且污染环境容量较大的情况下，给出种群弱平均持续生存、一致持续生存和绝灭的充分条件．     

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.     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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