These threats can be described in four concentric rings .
这些威胁可以说是四个同心圆。
Place a picture of concentric circles a few feet away and stare at it .
在离自己几英尺远的地方挂一张画有同心圆的图，注视着这张图。
To cloak something , concentric rings of the metamaterial are placed around the object to be concealed .
为了遮盖某件物体，由超材料制成的同心环被放在要隐藏的物体周围。
The minute droplets in the layer of fog deflect sunlight in such a way to produce concentric rings and overlapping colors .
迷雾层内微小水滴在衍射过程中使阳光偏转而产生同心的圆环和重叠的颜色。
Images of black-hole collisions that happened before the new bang may thus imprint themselves as concentric circular marks in the emerging cosmic microwave background .
