A fairly purepreparation can be obtained through two runs of low-speed centrifugation and a single run of high-speed centrifugation in sucrose gradient.
主要是经过两次低速离心，一次蔗糖梯度超速离心，即可得到一定纯度的细胞膜。
2
The preparation of pure pyridinium dichromate is described.
三氧化铬与吡啶反应制备吡啶重铬酸盐。
3
The antiosmosis equipments has been extensively used in industrial pure water preparation, compared with traditional technology. it has obvious economic benefit and social benefit.