Centrifugation is a process used to seperate or concentrate materials suspended in a liquid medium. The theoretical basis of this technique is the effect of gravity on particles (including macromolecules) in suspension. Two paticles of different masses will settle in a tube at different rates in response to gravity. Centrifugal force (measured as xg, gravity) is used to increase this settling rate in an instrument called a centrifuge. 

    Centrifuges are devices used in a variety of scientific and technical applications which spin carrier vessels (centrifuge tubes) at high totation speeds and very high cenfugal force.The centrifugal force (expressed as #gravities or, #xg) generated is proportional to the rotation rate of the rotor (in rpm) and the distance bitwiin the rotor center and the centrifuge tube.Therefore, a given centrifuge may use multiple rotor size to give flexibility in choosing centrifugation conditions. Each centrifuge has a special graph, a nomograph, or a table which relates rotation rate (rpm) to centrifugal force (xg) for each size of rotor it accepts.

    离心是一个用于分离或浓缩悬浮在液体介质中的物质的工艺。该技术的理论基础是重力对悬浮液中粒子(包括大分子)的作用。不同质量的两种粒子在重力作用下以不同的速率沉降。离心力(以xg计量 ) 被 用在一个叫作离心机的仪器上来增加沉降速率。

    离心机是一些用在科技领域的设备，这些设备高速转动承载容器(离心管)产生很高的离心力。所产生的离心力(以#重力或#g表示)与转鼓的转速(rpm)以及转鼓中心到离心管的距离有一定的比例关系。因而，为了在选择离心条件时具有灵活性，一台离心机可以使用多种转鼓尺寸。每台离心机都有一条特殊的曲线，一条诺莫曲线或一张表格，来说明所采用的每种尺寸的转鼓的转动速率(rpm)所产生的离心力(xg)。