e/Bispherical coordinates

Information
has gloss	eng: Bispherical coordinates are a three-dimensional orthogonal coordinate system that results from rotating the two-dimensional bipolar coordinate system about the axis that connects the two foci. Thus, the two foci F_1} and F_2} in bipolar coordinates remain points (on the z-axis, the axis of rotation) in the bispherical coordinate system.
lexicalization	eng: bispherical coordinates
instance of	(noun) a system that uses coordinates to establish position reference system, coordinate system, frame of reference, reference frame

Meaning
Chinese
has gloss	zho: <div style="float:right;width:350px;"> 雙球坐標系是一種三維正交坐標系。設定二維雙極坐標系包含於 xz-平面。設定這雙極坐標系的兩個焦點 F_1}\,\! 與 F_2}\,\! 包含於 z-軸。將雙極坐標系繞著 z-軸旋轉，則可以得到雙球坐標系。在這二維雙極坐標系裏，坐標 \sigma\,\! 的等值曲線是圓圈。經過旋轉後，圓圈變成一個環面，而圓圈的圓心變成一個包含於 xy-平面的圓圈，稱為環心圓。稱環心圓至環面的距離為環小半徑。
lexicalization	zho: 雙球坐標系

Media
media:img	Apollonian circles.png
media:img	Bipolar coordinates.png
media:img	Bispherical coordinates.png