较宽频带分布式放大器的设计问题

本文讨论了通频带较宽(可用频宽为150兆赫至数百兆赫)之低通分布式放大器设计中所遇到的各项问题。文中对电子管的输入和输出阻抗进行了较精确的计算,并根据计算结果着重地讨论了输入电容和输入电导变化对分布式放大器较高频部分特性的影响。对于包括引线电感在内的傅输线电感的设计问题也进行了讨论。根据这些计算和讨论的结果提出了较为合理而易于实现的较宽频带的分布式放大器的设计方法。最后从实验结果加以说明。     

Characteristics and formation of [AlO_4Al_(12)(OH)_(24)(H_2O)_(12)]~(7+) in electrolysis process

[AlO4Al12(OH)24(H2O)12] + (Al13) formation in electrolysis process is studied. The results detected by27Al NMR spectroscopy show that high content of Al13 polymer is formed in the partially hydrolyzed aluminum solution prepared by controlled electrolysis process. In the produced electrolyte of total Al concentration ([AlT]) 2.0 mol · L-1 with a basicity (B = OH/Al molar ratios) of 2.0, the content of Al13 polymer is over 60% of total Al. Dynamic light scattering shows that the size distribution of the final electrolyte solutions ([AlT] = 2.0 mol · L-1) is trimodal with B = 2.0 and bimodal with B = 2.5. The aggregates of Al13 complexes increase the particle size of partially hydrolyzed aluminum solution.     

[AlO4Al12(OH)24(H2O)12]7+的电化学合成及表征

研究了[AlO₄Al₁₂(OH)₂₄(H₂O)₁₂]⁷⁺ (Al₁₃)的电化学合成方法, 并采用²⁷Al NMR法和激光光散射等方法对其形态进行表征. ²⁷Al NMR法证明在电解制备的总铝浓度(Al_T)为2.0mol/L, 碱化度(B )为2.0的部分水解铝溶液中, Al₁₃占总铝量的60%以上. 激光光散射实验结果表明, 电解法制备的Al_T=2.0 mol/L, B=2.0的部分水解铝溶液存在三种粒径分布, Al₁₃以单体和多聚体的形式存在. 在B为2.5时颗粒粒径变大, 存在两种粒径分布, 并且大部分Al₁₃以多个Al₁₃聚集的形态存在.