液相施主及高钙添加对PTC材料性能的影响

采用液相施主掺杂和高钙添加相结合的方法,制得性能优良,适合程控电话交换机防雷击、防过流用的耐强电限流器件的PTC材料。在液相施主Y(NO3)3的添加量(摩尔分数)为0.4%,CaCO3添加量(摩尔分数)为15%时,得到了室温电阻率为140?·cm,居里点tC为74℃,阻温系数α为13.9%℃–1,升阻比lg(ρmax/ρmin)为7.2,耐压强度Vb≥260V/mm的PTC材料。     

Optimized preparation of zinc-inorganic antibacterial material containing samarium using response surface methodology

A Box-Behnken design(BBD) of response surface methodology(RSM) was used to optimize the preparation of the Zn-Sm antibacterial white carbon black by the sol-gel method. The statistical analysis of the results showed that the particle size of the Zn-Sm antibacterial white carbon black was significantly affected by the reaction time, reaction temperature and the stirring speed. According to analysis of variance(ANOVA), the values of the determination coefficient(R2=0.9821) and the "Pred R-Squared" of 0.8227 were in reasonable agreement with the "Adj R-Squared" of 0.9591. It was indicated that this model could be used to navigate the design space. The optimized reaction time, temperature and the stirring speed were 0.88 h, 87.83 oC, and 473.45 r/min, respectively. In addition, the bacteriostasis rate of the product was about 97.92%.     

整体开放空间车站和典型车站设计——浅谈广佛线菊树站的车站建筑方案设计

广州市广佛线菊树站车站方案设计中提出了整体开放空间车站的设计理念。整体开放空间车站设计新颖，体现以人为本的设计原则；典型车站规模较小，车站各功能布置成熟合理……     

浅析某电厂机组在停机过程中出现励磁时序控制跳闸的原因

本文针对某水力发电厂机组在停机的过程中出现励磁时序控制跳闸不正常现象的发生,浅析其原因.     

低电阻率、大升阻比BaTiO_3基PTCR陶瓷材料

研究了Sb2O3和Ta2O5双施主掺杂对低电阻率的BaTiO3陶瓷PTC特性的影响。在Sb2O3和Ta2O5的摩尔分数分别为0.1%和0.01%时,得到了室温电阻率为4.59 Ω·cm,升阻比为3.4的优质PTCR陶瓷材料。通过XRD 、SEM显微结构分析;复阻抗测试,估计晶粒和晶界电阻值,探讨了Sb2O3和Ta2O5的作用机制。