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.

    離心是一個用于分離或濃縮懸浮在液體介質中的物質的工藝。該技術的理論基礎是重力對懸浮液中粒子(包括大分子)的作用。不同質量的兩種粒子在重力作用下以不同的速率沉降。離心力(以xg計量 ) 被 用在一個叫作離心機的儀器上來增加沉降速率。

    離心機是一些用在科技領域的設備，這些設備高速轉動承載容器(離心管)產生很高的離心力。所產生的離心力(以#重力或#g表示)與轉鼓的轉速(rpm)以及轉鼓中心到離心管的距離有一定的比例關系。因而，為了在選擇離心條件時具有靈活性，一臺離心機可以使用多種轉鼓尺寸。每臺離心機都有一條特殊的曲線，一條諾莫曲線或一張表格，來說明所采用的每種尺寸的轉鼓的轉動速率(rpm)所產生的離心力(xg)。