充分利用了的

By constructing a Liapunov function, we obtain some sufficient conditions which ensure the persistence of the first system, and the existence of periodic solutions of the second system which is established by using coincidence degree theory.

另外，我们也利用重合度理论得到了第二个系统正周期解存在的充分条件。

By using Mawhin\'s continuous theorem and liapunov function, sufficient conditions for the existence and globally asymptotic stability of positive periodic solutions of three systems are derived, respectively.

我们还利用Mawhin连续性定理分别建立了两个系统正周期解存在的充分条件。

This paper uses contraction mapping approach in order to give sufficient condition for solvability about this kind of matrix equation in given conditions.

文章利用压缩映射思想给出了一类矩阵方程在给定条件下有解的充分条件。

The existence of positive periodic solutions of this system is established by using coincidence degree theory.

利用重合度理论得到了该系统正周期解存在的充分条件。来源：ABC79论文网www.abclunwen.com

Repetitive mortgage comes into being when the pledger wants to make the best use of the value of the pledge and fully realize the financing function of the pledge.

抵押人为最大限度利用抵押物价值，充分实现抵押物融资功能的愿望，便出现了重复抵押。

Then using the Zhengding quadratic form theory, had proven a function of many variables condition extreme value's sufficient condition, and has given its application example.

而后利用正定二次型理论，证明了多元函数条件极值的一个充分条件，并给出了其应用的例子。

By systemic researching and simulating experiment, the text gains such results as follows,1. On the base of sufficiency research on the oil-gas hydrocarbon systemic chemistry composing and the physical chemistry characters, we traverse the mechanism of the paraffin's deposition. Then we consider that paraffin deposition is a complex process ofphysical chemistry, which includes more than one single mechanism.2. Traversing and comparing the literature in detail on different factors that has effect on paraffin deposition, the available experimental methods on paraffin deposition, prevention of paraffin deposition, and removing of the deposited paraffin on the spot.3. Ameliorated the laser equipment of solid particle inspecting system and the corresponding test methods. Determine WCT of dead oil and live oil from KS101 well under different pressure with this system. The result implies that dead oil has opposite regulation on paraffin deposition temperature to live oil.4. A vapor-liquid-solid envelop is drawn by superposition regular vapor-liquid envelop and WCT curve thereby explained that the departure and quick raising of the curve in the low temperature zone is caused by the appearance of paraffin in solid phase.5. Estimation is made to determine the depth of paraffin deposition in the well.

通过系统的研究和实验模拟，本文取得了以下研究成果：(1)在充分调研油气烃类体系的化学组成及其物理化学特征的基础上，详细研究了石蜡沉降的机理，认为石蜡沉积是一个复杂的物理化学过程，是多种机理共同作用的结果；(2)深入调研并综合阐述了影响石蜡固相沉积的各种主要因素，对目前国内外常用的有机固相沉积实验研究方法和现场清防蜡措施也做出详尽的描述，并加以对比评价；(3)改进了油气藏开发重点实验室自行研制组装的高温高压下测定固相沉积的激光装置和测试方法，并用该套设备测定出柯深101井的井口脱气油样和凝析气平衡油样不同压力下的析蜡点，实验结果表明，脱气油和平衡油析蜡规律相反；(4)将常规气-液两相相图和析蜡曲线叠加得到了气—液—固三相相图，从而解释了气-液两相等液量线在低温区域偏离正常并快速上翘是由于体系有石蜡固相出现；(5)利用实验测试的析蜡温度预测析蜡位置，表明只有在距井口465m油管以上会有蜡析出。

Starting from the definition of almost normal subgroup , the author gives some interesting results about almost normal subgroups and the sufficient conditions for a finite group to be solvable.

利用几乎正规的定义对有限群G作了一些研究，得到了几乎正规子群的一些性质，并给出了有限群为可解群的几个充分条件。

In the first section of the part three, the criteria for globally stable equilibrium in n-dimensional predator-prey model are obtained.

第三部分对生态问题的研究第一节利用二次型理论研究了一类n维环状自治系统有密度制约模型，得到了判别此类系统稳定平衡点的充分条件。

Our results improve the former results. For periodic Jacobi matrix, some new spectral properties of periodic Jacobi matrix are given by studying the relationship of the eigenvalues of periodic Jacobi matrix and its n—1 principal submatrix. Applying these spectral properties, we present a necessary and sufficient condition for the solvability of an inverse problem of periodic Jacobi matrices and discuss the number and the relationship of its solutions. Furthermore, we propose a new algorithm to construct its solution and compare it with the former algorithms. As this inverse problem of periodic Jacobi matrix usually has multiple solutions as many other eigenvalue inverse problems, we study the uniqueness of this problem. And a necessary and sufficient condition is given to ensure its uniqueness, under which an algorithm is presented and the stability analysis is also given. Finally, we put forward a new inverse problem for periodic Jacobi matrix which has not been solved.

对周期Jacobi矩阵特征值反问题，通过研究周期Jacobi矩阵与其n-1阶主子阵特征值的关系，给出了周期Jacobi矩阵的一些新的谱性质；利用这些谱性质，研究了一类周期Jacobi矩阵特征值反问题，用新的方法推导出了该类特征值反问题有解的充分必要条件，并讨论了解的个数以及解与解之间的关系；此外，提出了一种新的构造周期Jacobi矩阵反问题解的数值算法，并与前人的算法做了一定比较；由于周期Jacobi矩阵特征值反问题和其他很多特征值反问题一样往往存在多个解，本论文给出了周期Jacobi矩阵反问题解唯一的充要条件，并发现周期Jacobi矩阵特征值反问题的解唯一当且仅当构造的矩阵满足一定的条件；在解唯一的情况下，给出了构造唯一解的数值算法，并做了相应的稳定性分析；最后，提出了一类新的有待于解决的周期Jacobi矩阵特征值反问题。

We have no common name for a mime of Sophron or Xenarchus and a Socratic Conversation; and we should still be without one even if the imitation in the two instances were in trimeters or elegiacs or some other kind of verse--though it is the way with people to tack on 'poet' to the name of a metre, and talk of elegiac-poets and epic-poets, thinking that they call them poets not by reason of the imitative nature of their work, but indiscriminately by reason of the metre they write in.

索夫农 、森那库斯和苏格拉底式的对话采用的模仿没有一个公共的名称；三音步诗、挽歌体或其他类型的诗的模仿也没有——人们把&诗人&这一名词和格律名称结合到一起，称之为挽歌体诗人或者史诗诗人，他们被称为诗人，似乎只是因为遵守格律写作，而非他们作品的模仿本质。

The relationship between communicative competence and grammar teaching should be that of the ends and the means.

交际能力和语法的关系应该是目标与途径的关系。