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21.
This paper investigates the absorptive spectral lines of four-level
atomic system driven by a coupling, probe and microwave fields. Due
to the perturbation of the microwave field, the original
electromagnetically induced transparency is changed to
electromagnetically induced absorption and the absorptive spectral
line can be very narrow. This ultranarrow spectral line has
potential applications to the microwave atomic frequency standard and
the measurement of very weak magnetic field. 相似文献
22.
采用电感耦合等离子体发射光谱法测定锂离子电池石墨类负极材料中铁含量,对测定结果的不确定度进行评定。根据JJF 1059.1—2012《测量不确定度评定与表示》和测定过程中的风险因素,建立数学模型和因果图,分析不确定度来源,计算合成标准不确定度和扩展不确定度。结果表明,测量重复性、标准曲线拟合、提取回收率对测定结果影响较大。当样品中铁含量为495.00 mg/kg时,其扩展不确定度为U=29.89 mg/kg,k=2。 相似文献