outer boundary

基本解释

Firstly, according to iris is a kind of cirque, algorithm based on geometrical feature is used to locate outer boundary of iris cursorily.
首先，利用虹膜为环形的特点，采用几何算法粗略得出虹膜外边界的圆心和半径。
Under these circumstances, reconnection takes place along a wide equatorial belt, opening up nearly the entire outer boundary of the magnetosphere to the solar wind.
在这种情况下，磁力线重连会在赤道面上宽广的带状区域内发生，几乎把整个磁层外围边界都打开，放太阳风进来。
To the iris' outer boundary, we use the feature of the iris' structure and mathematical means to verify whether the iris outer boundary points are correct, and calculate the correct ones if necessary.
本方法主要针对定位容易出现错误的外边界，利用虹膜的结构特征和数学手段，对得到的虹膜外边界点进行验证，必要时通过计算得到准确的外边界点。

Goldman has to stay out ahead of its rivals in trying daring and innovative approaches that push the outer edge of the boundary between what is okay and what may not be.
FORBES: Magazine Article
But we are the only species to have defined a geological period by our activity — something usually performed by major glaciations, mass extinction and the colossal impact of objects from outer space, like the one that defines the upper boundary of the Cretaceous.
FORBES: On The Anthropocene Age