High-Temperature/Field Alternating-Current Behavior of ZnO-Based Varistors

The ac electrical response of the grain boundary in the ZnO–Bi₂O₃-based varistor system (in the frequency range 10⁻²≤f≤10⁷ Hz) has been analyzed using complex plane analysis techniques as a function of temperature (90°≤T≤150°C) and electric field (E_60%lmA/cm2≤E≤E_lmA/cm2). The high-temperature/field data were best represented in the impedance plane. The lumped parameter equivalent circuit representation, containing a voltage variable resistive element associated with the grain boundary, was in agreement with a model previously reported in the literature. The resulting equivalent circuit representation of the grain-boundary response consisting of a resistance and a capacitance are interpreted in terms of various phenomena occurring at the electrical thickness of the grain boundary.     

合成纤维用的微细紫外线吸收剂

近几年 ,对于采用纺织品作为一种防止过度曝晒而产生损害作用的方法 ,已经引起了激烈的争论。本文将讨论以前文献所报导过的采用超细TiO2 作为各种解决办法可供选择的概念。     

Thermoluminescence of ZnO

The thermoluminescent behavior of polycrystalline ZnO was studied as a function of the temperature and partial pressure of oxygen of the heat treatment. Two peaks were observed, a broad peak at about 150°K and a well defined peak at 182°K. Analysis of the data obtained from the high temperature peak is consistent with the existence of a defect complex involving a copper impurity at 0.4 eV and a zinc vacancy 2.4 eV below the conduction band.