简介：PolysiliconMicroelectromechanicalsystems(MEMS)arethesubjectofintensiveresearches.SurfacechemistryandtopographyofaMEMSteststructurefabricatedatSandiaNationalLaboratory,USA,werestudiedbymeansofscanningelectronmicroscopy(SEM),X-rayphotoelectronspectroscopy(XPS)andatomicforcemicroscopy(AFM).XPSC()andSi2,spectrafromthepolysilieoncomponents,siliconnitridesubstrateandareferencesiliconwaferwerecompared.Theresultsconfirmthepresenceofaself-assembledmonolayer(SAM)ontheMEMSsurface.Anisland-likemorphologywasfoundonbothpolysiliconandsiliconnitridesurfacesoftheMEMS.Theislandstaketheformofcaps,beingupto0.5μmindiameterand20nminheight.Itisconcludedthattheco-existenceofcolumnargrowthandequiaxedgrowthduringthelowpressurechemicalvapordeposition(LPCVD)oftheselayersleadstotheobservedmorphologyandtheislandsarecapstothecolumnarstructures.

简介：采用加速溶剂萃取仪（ASE）以甲醇为溶剂提取黄芪药材中的黄芪甲苷,利用高效液相色谱-蒸发光散射检测器（HPLC-ELSD）进行含量测定.考察了不同的提取温度、提取时间、循环次数等条件下的提取效果,确定了最佳的ASE提取条件.同传统的提取方法相比,ASE法溶剂用量少,耗时短,提取效率高.并通过回收率和精密度的测定,证明加速溶剂萃取技术完全可以用于中药材中的黄芪甲苷的提取.