具有阶段时滞结构的生态-流行病模型的生物防治策略

分析一个具有一般形式的疾病感染率和功能反应函数的阶段时滞结构的捕食者-食饵(天敌-害虫)模型,利用人工脉冲周期投放有病的害虫和天敌去控制害虫.通过脉冲方程理论,证明了当周期投放量达到一个临界点时,害虫将灭绝;并进一步证明了当投放量控制在一定范围之内时,害虫的密度将在农作物经济危害水平之下并与天敌共存.     

具有阶段结构的害虫-天敌模型的脉冲控制

研究了一类具有阶段结构的害虫-天敌系统。当使用杀虫剂消灭害虫时,研究脉冲形式的控制,得到了无天敌时系统存在稳定的周期解。然后利用分支理论,讨论害虫-天敌模型的非平凡周期解,周期解由稳定变成不稳定的。     

一类具有脉冲的捕食与被捕食系统的动态行为

研究具有周期脉冲的捕食与被捕食模型的动态行为.通过喷洒杀虫剂和投放天敌的周期不同,得到了捕食系统害虫灭绝周期解的全局稳定性的临界值,分析喷洒杀虫剂和投放天敌的周期如何影响生物控制,为害虫治理提供了策略基础.     

一个阶段时滞结构的生态-流行病模型的害虫综合防治策略

分析一个阶段结构的捕食者-食饵（天敌-害虫）模型,利用人工周期定量地投放有病的害虫和天敌去治理害虫．通过脉冲微分方程理论,证明了周期投放量p和q满足β2q（exp（mT）-1/（exp（d4T）-1）exp（（m＋d4）T）-1）＋β1p/exp（d3T）-1〉be^-d1τ时,害虫幼虫及成虫将灭绝,而病虫和天敌的密度驱于一个稳定的水平,并进一步证明了当周期投放量p和q满足be^-d1τ-d2E〈β2q（exp（mT）-1/（exp（d4T）-1）exp（（m＋d4）T）-1）＋β1p/exp（d3T）-1〉be^-d1τ时,害虫的密度将在经济受害损失允许水平之下并与天敌共存．     

一个阶段时滞结构的生态-流行病模型的害虫综合防治策略

分析一个阶段结构的捕食者-食饵（天敌-害虫）模型,利用人工周期定量地投放有病的害虫和天敌去治理害虫．通过脉冲微分方程理论,证明了周期投放量p和q满足β2q（exp（mT）-1/（exp（d4T）-1）exp（（m＋d4）T）-1）＋β1p/exp（d3T）-1〉be^-d1τ时,害虫幼虫及成虫将灭绝,而病虫和天敌的密度驱于一个稳定的水平,并进一步证明了当周期投放量p和q满足be^-d1τ-d2E〈β2q（exp（mT）-1/（exp（d4T）-1）exp（（m＋d4）T）-1）＋β1p/exp（d3T）-1〉be^-d1τ时,害虫的密度将在经济受害损失允许水平之下并与天敌共存．     

一类捕食-食饵系统绝灭的充分条件

研究了一类具有生物和化学控制(周期释放天敌和喷洒杀虫剂)的两食饵-两捕食者模型的动力学性质.通过线性周期脉冲方程的F loquet理论和小幅扰动方法,证明当脉冲周期小于某个临界值时,存在一个全局渐近稳定的两个害虫根除周期解.     

状态依赖的脉冲微分方程模型的最优周期控制策略

在研究了混合害虫模型的最优控制策略、关于常数和比例投放天敌的最优控制策略的基础上,又进一步讨论周期控制下的花费最小的控制策略,即周期投放天敌和周期综合控制策略.数值结果表明,最小花费上周期综合控制是最优的.     

一类害虫种群有疾病传播的害虫防治模型

考虑了脉冲投放病毒和脉冲投放天敌的害虫综合控制模型.运用Floquet乘子理论,脉冲微分方程比较定理,讨论了模型的害虫灭绝周期解全局渐进稳定性;选取内禀增长率为分支参数,利用分支定理,给出了系统存在正周期解的充分条件.     

一类具有Allee效应的害虫综合治理捕食-食饵模型的动力学分析

考虑了一类具有状态反馈脉冲控制和Allee效应的捕食-食饵模型,其中天敌的投放量及杀虫剂的使用强度均线性依赖于害虫的控制水平.首先,分析了无控制系统解的正性及有界性,并给出了正平衡态全局渐近稳定的充分条件.其次,借助于后继函数方法讨论了控制系统阶1周期解的存在性,并给出了阶1周期解稳定的条件.为了确定最佳的天敌投放量和杀虫剂强度,以投入成本最小化为目标进行了优化模型构建与分析.结果表明,基于本文所提出的控制策略,害虫数量可控制在经济损害水平之下并呈周期性变化.     

具有脉冲投放益虫生物控制害虫的捕食-食饵模型

 讨论了具有阶段结脉冲时滞HollingII功能反应的捕食模型,其中天敌（益虫）进行人工脉冲周期投放,害虫具有阶段结构及成熟期的时滞现象,并进行了系统的数学及生物方面的研究。首先利用离散动力系统的频闪映射得到了害虫根除周期解的存在性,并且利用脉冲及时滞微分方程的基本知识证明了该害虫根除周期解的唯一性和全局吸引性。进一步证明了当天敌的投放量或者投放周期在一定的范围内,能够控制害虫在作物的经济危害水平(EIL)运行的情况下使天敌与害虫可以共存。得出的结论为害虫的生物治理提供了策略基础。     

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     

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     

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

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