Colloidal carbon spheres with hydrophilic surface were synthesized using glucose as precursor by hydrothermal methods.Amorphous SiO2,anatase TiO2 and cassiterite SnO2 hollow spheres were successfully prepared using co...Colloidal carbon spheres with hydrophilic surface were synthesized using glucose as precursor by hydrothermal methods.Amorphous SiO2,anatase TiO2 and cassiterite SnO2 hollow spheres were successfully prepared using colloidal carbon spheres as template in conjunciton with the sol-gel method.The hollow spherical structures could be confirmed by TEM and SEM.The BET surface area of hollow spheres were about 183.8 m2/g,32.5m2/g,and 74.3m2/g,respectively.展开更多
文摘Colloidal carbon spheres with hydrophilic surface were synthesized using glucose as precursor by hydrothermal methods.Amorphous SiO2,anatase TiO2 and cassiterite SnO2 hollow spheres were successfully prepared using colloidal carbon spheres as template in conjunciton with the sol-gel method.The hollow spherical structures could be confirmed by TEM and SEM.The BET surface area of hollow spheres were about 183.8 m2/g,32.5m2/g,and 74.3m2/g,respectively.
基金supported by the Major State Basic Research Development of China(2007CB513108)special program of Hunan11th five-year,P.R.China(2006SK1001)the Key Research Project of Hunan,P.R.China(2007-985-2)
文摘浮游动物在食物链能量流动与物质循环中发挥着重要作用,能将摄入的浮游植物转化为不同形态的碳,在海洋碳循环中发挥重要作用。应用14C标记示踪方法,定量分析海洋浮游动物褶皱臂尾轮虫Brachionus plicatilis摄入碳的碳同化与碳排放。喂食不同密度小球藻Chlorella sp.(1×10~5个/m L、5×10~5个/m L、1×10~6个/m L)后,褶皱臂尾轮虫对小球藻碳的同化率(AE)为34%—51%,呈现随饵料密度增加而减小的趋势;未被轮虫同化的碳,主要以溶解有机碳(DOC)的形态排放到水体中,DOC占碳排放的比例为37%—51%,随着饵料密度增加而增加;二氧化碳(CO2)的比例为15%—40%,随着饵料密度增加而减小;颗粒有机碳(POC)占碳排放的比例较少,为23%—34%,随着饵料密度的增加而增加。此外,分析褶皱臂尾轮虫排放DOC的粒径组成,发现低分子量有机碳(LMW,<3 k Da)的量大于胶体有机碳(COC,3 k Da—0.22μm)的量,COC占DOC比例为33%—43%;LMW占DOC比例为57%—67%。本研究结果表明,浮游动物可把相当部分食物中的碳转化为DOC,排放到水体中为细菌所利用,在海洋碳循环中发挥重要作用。
