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Effects of barium on the nonlinear electrical characteristics and dielectric properties of SnO2-based varistors 下载免费PDF全文
The effects of barium on electrical and dielectric properties of the SnO_2·Co_2O_3·Ta_2O_5 varistor system sintered at 1250℃ for 60min were investigated. It is found that barium significantly improves the nonlinear properties. The breakdown electrical field increases from 378.0 to 2834.5V/mm, relative dielectric constant (at 1kHz) falls from 1206 to 161 and the resistivity (at 1kHz) rises from 60.3 to 1146.5kΩ·cm with an increase of BaCO_3 concentration from 0mol% to 1.00mol%. The sample with 1.00mol% barium has the best nonlinear electrical property and the highest nonlinear coefficient (α=29.2). A modified defect barrier model is introduced to illustrate the grain-boundary barrier formation of barium-doped SnO_{2}-based varistors. 相似文献
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在新课程、新高考、新教材(简称“三新”)改革背景下,物理教师如何适应新高考、用好新教材,如何多渠道开发整合实验资源是需要解决的关键问题.在新教材使用的教学实践中,探索研究了在物理教学中进行实验资源开发的4种有效路径与策略,并以“安培力”一课为例,具体呈现课堂教学各个环节的实验设计方案及对应的开发路径与策略. 相似文献
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Density functional theory within the local density approximation is used to investigate the effect of the oxygen vacancy on the LaGaO_3/SrTiO_3(001) heterojunction. It is found that the energy favorable configuration is the oxygen vacancy located at the 3~(rd) layer of the STO substrate, and the antiferrodistortive distortion is induced by the oxygen vacancy introduced on the SrTiO_3 side. Compared with the heterojunction without introducing oxygen vacancy, the heterojunction with introducing the oxygen vacancy does not change the origin of the two-dimensional electron gas(2DEG), that is, the 2DEG still originates from the d_(xy) electrons, which are split from the t~(2g) states of Ti atom at interface; however the oxygen vacancy is not beneficial to the confinement of the 2DEG. The extra electrons caused by the oxygen vacancy dominantly occupy the 3d_(x~2-y~2) orbitals of the Ti atom nearest to the oxygen vacancy, thus the density of carrier is enhanced by one order of magnitude due to the introduction of oxygen vacancy compared with the density of the ideal structure heterojunction. 相似文献
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多环芳烃的危害与防治 总被引:45,自引:0,他引:45
多环芳烃由于其致癌性、致突变性而受到广泛关注。本文介绍了多环芳烃的来源、种类、分布及性质,阐明了多环芳烃对人体的危害,并对减少其污染的防治措施进行了讨论。 相似文献
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评述了近年来铽的荧光光度分析的进展情况,就其方法、显色剂、线性范围以及干扰情况对近年来国内铽的荧光光度分析进行了综述,引用文献34篇。 相似文献
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研究了Sr对新型(Co, Nb)掺杂SnO2压敏材料微观结构和电学性质的影响.当SrCO 3的含量从零增加到1.50mol%时,(Co, Nb)掺杂SnO2压敏电阻的击穿电压从240V/mm猛增 到1482V/mm.样品的微观结构分析发现, 当SrCO3的含量从零增加到1.50 mol%时, SnO2的晶粒尺寸迅速减小.晶界势垒高度测量揭示,SnO2晶粒尺寸的迅速减小是击穿
关键词:
碳酸锶
二氧化锡
势垒
电学非线性 相似文献
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The first-principles calculations are employed to investigate the stability, magnetic, and electrical properties of the oxide heterostructure of LaAlO3/SrTiO3(110). By comparing their interface energies, it is obtained that the buckled interface is more stable than the abrupt interface. This result is consistent with experimental observation. At the interface of LaAlO3/SrTiO3(110) heterostructure, the Ti–O octahedron distortions cause the Ti t2 gorbitals to split into the twofold degenerate dxz/dyz and nondegenerate dxy orbitals. The former has higher energy than the latter. The partly filled two-fold degenerate t2 gorbitals are the origin of two-dimensional electron gas, which is confined at the interface. Lattice mismatch between LaAlO3 and SrTiO3leads to ferroelectric-like lattice distortions at the interface, and this is the origin of spin-splitting of Ti 3d electrons. Hence the magnetism appears at the interface of LaAlO3/SrTiO3(110). 相似文献