摘要：
There was a huge link between Cao Yun (漕运 cancal transport) and the long extension of Chinese feudal society. 'Cao Yun' consolidated tile stabilization of autocracy which was the material base of strengthening the central autocracy of feudal dynasty'; the characteristic of the robbery of 'Cao Yun' restrained the social economy's development immensely, especially, delaying the pace of advance in the developed district; 'Cao Yun' limited tile development of civil market in some level, and the prosperity brought by 'Cao Yun' along the river was instable, which Ins difficult to trigger the substantial change of the economy in the district; 'Cao Yun', which was like a yoke, fixed the peasants in the land, and intensified their conservative consciousness unceasingly.
期刊：
Journal of Differential Equations,2000年164(1):1-15 ISSN：0022-0396
通讯作者：
Xiao, DM
作者机构：
[Xiao, DM; Li, WX] Department of Mathematics, Central China Normal University, Wuhan, 430079, People's Republic of China
通讯机构：
[Xiao, DM ] ;Cent China Normal Univ, Dept Math, Wuhan 430079, Peoples R China.
摘要：
In the first part of this paper, it is proved that the number of limit cycles of the competitive three-dimensional Lotka–Volterra system in R3+ is finite if this system has not any heteroclinic polycycles in R3+. In the second part of this paper, a 3D competitive Lotka–Volterra system with two small parameters is discussed. This system always has a heteroclinic polycycle with three saddles. It is proved that there exists one parameter range in which the system is persistence and has at least two limit cycles, and there exists other parameter ranges in which the system is not persistence and has at least one limit cycle.
摘要：
<正> 一、研究目的“教师效能感”（teacher’s sense of efficacy）是指“教师相信自己有能力对学生的学习产生积极影响的信念”。“教师效能感”一词最早出现在70年代。随着Bandura的社会学习理论的兴趣,研究者们开始运用Bandura的自我效能（self—efficacy）概念来研究教师的效能感。Bandura认为,自我效能是个人对自己在特定的情境中是否有能力去完成某种行为的期望。它包含两部分:结果期望和效能期望。结果期望是指个体对某一行为可能导致某一结果的推测;效能期望是指个体对自己实施某一行为的能力的主观判断。有的学
