火焰原子吸收法测定中药土大黄中四种微量元素的含量

目的运用火焰原子吸收光谱法测定中药土大黄根中的Fe、Zn、Mg、Ca等4种金属元素的含量。方法用浓HNO3-HClO4消解样品,采用标准曲线法测定其4种金属元素含量。结果所测的样品中含有丰富的人体必需微量元素,尤其是Ca含量极高。方法回收率在96．90％～102．3％之间,样品相对偏差小于5％。结论方法简单、准确,结果令人满意。     

Thermodynamics and weak cosmic censorship conjecture of an AdS black hole with a monopole in the extended phase space

The first law of black hole thermodynamics has been shown to be valid in the extended phase space.However,the second law and the weak cosmic censorship conjecture have not been investigated extensively.We investigate the laws of thermodynamics and the weak cosmic censorship conjecture of an AdS black hole with a global monopole in the extended phase space in the case of charged particle absorption.It is shown that the first law of thermodynamics is valid,while the second law is violated for the extremal and near-extremal black holes.Moreover,we find that the weak cosmic censorship conjecture is valid only for the extremal black hole,and that it can be violated for the near-extremal black holes,which is different from the previous results.     

铜催化N′-芳基苯磺酰肼的N′-芳基化反应

以N′-芳基苯磺酰肼作为芳基化试剂,在铜催化下,实现N′-芳基苯磺酰肼的自身N-芳基化反应。该反应以5 mol%的醋酸铜为催化剂,三乙胺为碱,甲醇为溶剂,常温下N′-芳基苯磺酰肼反应4~8 h,产率最高可达88%。产物结构经^1H NMR,^13C NMR和HR-MS(ESI)表征。