简述酸碱理论及其应用

酸碱理论是阐明何为酸碱,以及什么是酸碱反应的理论。最早提出酸碱概念的是Robert Boyle,在其理论基础上,酸碱的概念不断更新,逐渐完善,其中最重要的有:酸碱电离理论,酸碱质子理论与酸碱电子理论。历史上的酸碱理论名目众多,但都是针对有共同特征一类物质与反应提出的观点。它们各有其特点,又相互联系,相互补充,提高了人们对酸碱本质的认识。酸与碱的概念体现在大自然的方方面面,它对人们的生产生活有着重要的意义。     

Hierarchical porous carbon toward effective cathode in advanced zinc-cerium redox flow battery

Advanced zinc-cerium redox flow battery(ZCRFB) is a large-scale energy storage system which plays a significant role in the application of new energy sources. The requirement of superior cathode with high acitivity and fast ion diffusion is a hierarchical porous structure, which was synthesized in this work by a method in which both hard template and soft template were used. The structure and the performance of the cathode prepared here were characterized and evaluated by a variety of techniques such as scanning electron microscopy(SEM), transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), cyclic voltammetry(CV), linear sweep voltammetry(LSV), and chronoamperometry(CA). There were mainly three types of pore size within the hierarchical porous carbon: 2 μm, 80 nm, and 10 nm. The charge capacity of the cell using hierarchical porous carbon(HPC) as positive electrode was obviously larger than that using carbon felt; the former was 665.5 mAh with a coulombic efficiency of 89.0% and an energy efficiency of 79.0%, whereas the latter was 611.1 mAh with a coulombic efficiency of 81.5% and an energy efficiency of 68.6%. In addition, performance of the ZCRFB using HPC as positive electrode showed a good stability over 50 cycles.These results showed that the hierarchical porous carbon was superior over the carbon felt for application in ZCRFB.     

莲子心中黄酮类物质的提取和测定

采用碱溶酸析法和微波间歇加热提取法,成功地提取了莲子心中黄酮类物质.经HCl-锌粉反应和红外光谱鉴定,提取物为黄酮炎物质.另外,利用分光光度法,以芦丁标准品为标准对莲子心中的总黄酮进行了测定,其质量分数分别为4.135mg/g和6.266mg/g.同时讨论了时间对测定方法的影响,结果表明,显色时间在4min内稳定.