Sr3.96Al14O25:Eu2+ ,Dy3+ long persistent materials with different weights of H3BO3 prepared by the high temperature solid-state reaction method were characterized by X-ray powder diffraction (XRD), scanning electronic microscopy (SEM), photoluminescence spectra (PL), and thermoluminescence (TL). The results of XRD indicate that the 3% addition of H3BO3 favorable for the formation of pure phase Sr4Al14O25 , and SrAl12O19 was generated when there is a low content or high content of H3BO3 . The average grain sizes of samples grow bigger with an increase of H3BO3 . PL spectra show that the emission peak does not shift evidently and the emission intensity changes little, indicating that the different amount of H3BO3 has little influence on the crystal field. The decay characteristics and TL measurement show that H3BO3 affects the afterglow properties of Sr3.96Al14O25 :Eu2+ ,Dy3+ , because the increasing H3BO3 leads to more defects in the Sr4Al14O25 matrix.
Based on the self-consistent electron dynamic transport theory for multi-probe mesoscopic systems, we calculate the distribution of internal potential, charge density, and ac conductance of a two-probe mesoscopic conductor with wide trapezoid reservoirs, and study the contact effect. The results show that including the contact effect can make a significant difference to the frequency-dependent electron transport properties. In the nonzero frequency case, the internal potential and the charge density are complex with extremely small imaginary parts. Importantly, the imaginary part of the charge density gives rise to a real ac conductance (admittance), which corresponds to the charge-relaxation resistance.
