Effect of Ge-GeO2 co-doping on non-ohmic behaviour of TiO2-V2O5-Y2O3 varistor ceramics

An investigation was made into the effect of doping with the elemental crystal Ge or/and GeO₂ on the TiO₂-V₂O₅-Y₂O₃ varistor ceramics. The result shows that as the doping contents of V₂O₅ and Y₂O₃ are 0.5 mol%, respectively, co-doping with 0.3 mol% Ge and 0.9 mol% GeO₂ makes the highest α value (α = 12.8), the lowest breakdown voltage V_1mA (V_1mA = 15.8 V/mm) and the highest grain boundary barrier Φ_B (Φ_B = 1.48 eV), which is remarkably superior to the TiO₂-V₂O₅-Y₂O₃ varistor ceramics undoped with Ge and GeO₂ and mono-doped with Ge or GeO₂. The TiO₂-V₂O₅-Y₂O₃-Ge-GeO₂ ceramic has the prospect of becoming a novel varistor ceramic with excellent electrical properties.     

Ni-Mn粉末触媒中固溶碳的作用效果和机理初探

 在国产DS6×800A型六面顶压机上，对比研究了含与不含固溶碳的Ni-Mn粉末触媒，采用直热式静压触媒法合成金刚石的差异。实验表明：Ni-Mn粉末触媒中固溶碳的存在，不仅可以提高金刚石的合成单产、细化金刚石晶粒，而且在同工艺条件下，能得到晶形完整度较高的金刚石单晶。     

5-Br-PNPFF与镉的络合反应及其应用

不对称呋喃甲(月替)类化合物是有色金属的优良显色剂。本实验室新近合成的1-(5′-溴-2′-吡啶)-5-(4′-硝基苯)-3-(2′-呋喃)甲(月替)(5-Br-PNPFF)是该类试剂之一。具有下列结构式。     

影响金刚石合成的粉末触媒形态因素

采用相同成分体系的片状、球状Ni-Mn-Cu粉末触媒体为原料,在六面顶压机上进行人造金刚石高温、超高压合成的对比实验.结果表明:具有片状等不规则形状的NiMnCu粉末触媒合成工艺较球状同类粉末触媒合成工艺更稳定、易于掌握.针对上述结果,结合金刚石成核、生长过程中合成腔体内温度变化对上述实验结果进行了讨论.     

静压法高石墨转化率的金刚石合成研究

 选用Ni-Mn-C粉末触媒,在国产DS6×800A型铰链式六面顶压机上实现了高石墨转化率的金刚石合成,其石墨转化率可达90%以上。高石墨转化率金刚石的合成,不仅有助于提高金刚石的效率,而且还可以减化提纯后处理工序。