持续生存

• There are documents that showed two instable patches can reach stability by diffusion . delay is generally exists in the nature . and it has different impacts on different models . while both delay and diffusion exist at the same time . so single species nonautonomous delay diffusion model . i . e
  已有文献表明两个不稳定的斑块体系可以通过相互扩散而达到种群的持续生存。另一方面，时滞现象在自然界中是普遍存在的对于不同的模型，时滞对其稳定性的影响也是不同的。
• Asymptotic behavior of three differential systems tang hong - ji abstract : the system ' s asymptotic behavior is the solutions " behavior at / - > - i - xxlt iiicluds the stability of the solutions , the attractivity of the solutions , the oscillation of the solutions . the purpose of this paper is to investigate the asymptotic behavior of throe differential systems
  这些性质揭示了动力系统的长期行为，因而在生态学，经济学，神经网络等众多领域有着广泛的应用本文研究了三类微分系统解的渐近性质。在种群动力学的研究中，种群的持续生存是最基本，最有趣的课题之一。
• Because of the influence of enterprise ' s inherent reason and outside factors , the growing of enterprise generally lacks of impetus that directly influence the enterprise ' s sustained development . the average age - of enterprise is only 3 - 4 years and survival rate is only 20 % - 30 % during the recent 20 years
  近二十年来，由于中小型民营科技企业自身的原因以及外部环境因素的影响，据有关部门的统计，企业的成活率仅为20 % - 30 % ，平均寿命只有3 - 4岁，而且企业成长普遍缺乏后劲、直接影响了企业的可持续生存与发展。
• In the light of the recent work in biological models , especially in the chemostat models , the dissertation provides a systematic study on the asymptotical behaviour of some chemostat models built by delay or diffusion differential equations . the main contents and results in this dissertation are as follows : i ) the global asymptotic behavior of the chemostat model with the beddington - deangelies functional responses and time delays is studied . the conditions for the uniform persistence of the competing populations are obtained via uniform persistence of infinite dimensional systems
  本论文基于当前生物学模型，特别是恒化器模型的研究现状，深入系统的研究了时滞和扩散方程描述的几类恒化器系统的渐近性态，本文的主要内容包括以下几个方面：一、研究了具有beddington - deangelies功能性反应函数的时滞恒化器模型，利用无穷维连续动力系统的一致持续生存的理论给出了两竞争种群一致持续生存的充分条件，利用单调动力学系统得到了系统的全局渐近稳定性。
• This paper consists of three parts : we first consider the non - autonomous predator - prey system with both beddirigton - deangelis functional response and dispersion . by using comparison theorem of differential equation , we study the permanance of the system . after that , by constructing suitable lyapunov function , we obtain some sufficient condition which guarantee the existence of globally asymptotically stable almost periodic solution of the system
  本文研究三方面的内容：第一部分考虑具有扩散和beddington ? deangelis功能反应的捕食-食饵系统，利用微分方程比较原理得到该系统一致持续生存的条件；通过构造适当的lyapunov函数得到了该系统存在全局渐近稳定概周期解的充分条件。
• Our results imply that mutual interference in a species may result in coexistence of the two competing species and demonstrate that those time delays do not influence the competitive outcome of the organisms . ii ) the asymptotic behaviour of the chemostat model with mutual interference or without mutual interference is studied . for the two models with delay , the uniform persistence of the models are both proved under the conditions of the existence of the positive equilibrium
  二、研究了无种内竞争和有种内竞争的具有阶段结构的时滞恒化器模型的渐近性态，对于两类模型，都在正平衡点存在性的条件下证明了该系统的一致持续生存，对于两类相应的常微系统的模型，均在正平衡点存在性的条件下证明了该正平衡点的全局稳定性。
• In complementary case , sufficient conditions for uniform persistence and extinction of the population are obtained by the theory of uniform persistence of infinite dimensional dynamical systems . especially for the model with equal diffusion coefficients and zero death rates , the global attractivity of the unique positive steady - state solution is proved . in substitutable case , sufficient conditions for uniform persistence and extinction of population are also ob
  首先考虑了具有互补营养的扩散模型，得到了该系统中种群绝灭和一致持续生存的充分条件；并对营养和种群具有相同的扩散系数和种群零死亡率的模型，证明了该系统存在唯一的正平衡解，并证明了该平衡解的全局吸引性。
• The paper was written to give complete qualitative analysis to the optimal harvesting control problem of multi - species lotka - volterra mutually beneficial system and find available catching strategies which could make the populations sustainably developing . from the view of economical advantages the optimal harvesting tactics that maximize the profit on the basis of persisting existence of the populations was also considered
  本文要对很少有人研究的多种群互惠型lotka - volterra生态系统的捕获优化问题进行全面的定性分析，寻求使种群得以持续发展的较可行的捕获方案，并从经济利益的角度出发，考虑在种群得以持续生存的前提下使利润最大化的最优捕获策略