The design of new chiral ligands is the key in the development of transition metal catalyzed asymmetric synthesis. Many chiral diphosphine ligands have been pre
用γ能谱法和放射化学法对大气气溶胶中~(210)Pb的活度浓度进行测定,对比分析结果,γ能谱法能够满足大气环境气溶胶中~(210)Pb的常规监测。用γ能谱法对成都地区大气气溶胶中~(210)Pb活度浓度进行了为期两年的采样监测,年平均浓度为1.50 m Bq/m~3,浓度变化有明显的季节性特征,冬季高夏季低。