A GaAs/AlGaAs two-dimensional electron gas （2DEG） structure with the high mobility of μ2K= 1.78 × 10^6 cm^2/Vs has been studied by low-temperature Hall and Shubnikov de Hags （SdH） measurements. Quantum lifetimes related to all-angle scattering events reduced from 0.64 ps to 0.52 ps after i11uminating by Dingle plots, and transport lifetimes related to large-angle scattering events increasing from 42.3ps to 67.8ps. These results show that small-angle scattering events become stronger. It is clear that small-angle scattering events can cause the variation of the widths of the quantum Hall plateaus. 相似文献
In this paper, a sensitive accurate method for the determination of heterocyclic aromatic amines (HAAs) in cigarette smoke has been developed and validated using solid-phase extraction coupled with liquid chromatography–tandem mass spectrometry. A calibration curve was obtained with representative cigarette smoke using the standard addition method to compensate for matrix effects because the smoke of different cigarettes shows similar matrix effects. With this method, the accuracy of the method can be improved using a common analog of HAAs, which will greatly reduce the expense of using an isotope-labeled internal standard. Validation results showed that the method has high sensitivity (quantification limits of 0.08–0.56 ng cig−1), good reproducibility (RSD 6.37–9.31 %) and satisfactory recoveries (81.0–111 %). With this method, the emissions of HAAs in 30 commercial cigarette samples were analyzed and compared.
