Three new cucurbitacins were isolated from the BuOH extract of the rhizomes of Hemsleya lijiangensis. Their structures were elucidated as 23, 24 -dihydro cucurb
A positive Mg-Al-nitrate layered double hydroxides(LDHs) has been synthesized using a non-steady coprecipitation method.The shape.size,chemical composition,elec