first quadrant meaning in English

第一象限

The qualitative behavior of the system at the origin in the interior of the first quadrant is studied
对系统在原点的性态，我们作了全面的分析。
In the cases of and , there has no closed orbit to the system ( * ) in the first quadrant
这里，为某一负值，。对和不定号的情形，系统（ * ）在第一象限内均不存在极限环。
When , there exists at least one limit cycle to the system ( * ) in the first quadrant ; theorem 2 . when , there exsits at most one limit cycle to the system ( * ) in the first quadrant ; theorem 3 . when , there exactly exists one limit cycle to the system ( * ) in the first quadrant
我们得到下列结论：定理1 、当时，系统（ * ）在第一象限内至少存在一个极限环；定理2 、当时，系统（ * ）在第一象限内至多存在一个极限环，若存在必为稳定的；定理3 、当时，系统（ * ）在第一象限内存在唯一的极限环，且为稳定的。