High areal capacitance of FeOOH-carbon nanotube negative electrodes for asymmetric supercapacitors

The relatively low capacitance of negative electrodes, as compared to the capacitance of advanced positive electrodes, poses a serious problem, since this limits the development of asymmetric supercapacitor (SC) devices with a large voltage window and enhanced power-energy characteristics. We fabricate negative SC electrodes with a high capacitance that match the capacitance of advanced positive electrodes at similar active mass loadings, as high as 37?mg?cm^?2. Cyclic voltammetry, impedance spectroscopy, galvanostatic charge-discharge data and the power-energy characteristics of the asymmetric SC device exhibit good electrochemical performance for a voltage window of 1.6?V. Our approach involves the development and application of particle extraction through liquid-liquid interface (PELLI) methods, new extraction mechanisms and efficient extractors to synthesize α-FeOOH and β-FeOOH electrode materials. The use of PELLI allows agglomerate-free processing of powders, which facilitates their efficient mixing with multiwalled carbon nanotubes (MWCNT) and allows improved electrolyte access to the particle surface. Experiments to determine the properties of FeOOH-MWCNT composites provided insight into the influence of the electrode material and the structure of extractor molecules on the composite properties. The highest capacitance of 5.86?F?cm^?2 for negative electrodes and low impedance were achieved using α-FeOOH-MWCNT composites and a 16-phosphonohexadecanoic acid (PHDA) extractor. This extractor allows adsorption on particles, not only at the liquid-liquid interface, but also in the bulk aqueous phase and can potentially be used as a capping agent for particle synthesis and as an extractor in the PELLI method.     

锰铜基高阻尼合金中锌量的测定──硫氰酸盐萃取分离络合滴定法

基于甲基异丁基甲酮于稀盐酸介质中定量地萃取Ｚｎ￣（２＋）与ＣＮＳ￣－形成的络阴离子。从而达到与共存的锰、镍、铝、铬的完全分离。在有氟化物、硫脲存在时Ｆｅ￣（３＋）、Ｃｎ￣（２＋）和Ａｇ￣＋也不被萃取。有机相中的锌于ＰＨ５．５“六胺”缓冲介质中返萃取回水相，用ＥＤＴＡ滴定。在文中给定的条件下锌的一次被萃取率可达９９％以上，成功地解决了锰铜基高阻尼合金中共存离子对锌量测定的干扰问题。     

矩形垂直筛板的流体力学性能研究

在600mm的有机玻璃冷模塔中,用水-空气体系测定矩形垂直筛板的塔板压降、漏液和雾沫夹带等流体力学性能,确定了合理的塔板结构,使其具有较高的气液通量和较宽的操作范围,空塔动能因子最大可达3.0kg1/2(m1/2.s)-1,液流强度可达21.6m3/(m.h)。并对不同气液流量下塔板的流体力学实验数据进行关联和分析,得出了矩形垂直筛板的干板压降计算关联式以及漏液率随液流强度和空塔动能因子的变化关系,为矩形垂直筛板的设计提供了依据。与新垂直筛板相比,矩形垂直筛板具有更低的塔板压降。     

三聚甲醛萃取—精馏新工艺及过程优化

本文对采用Ｓ１和Ｓ２的混合物作为萃取剂的三聚甲醛萃取－精馏新工艺进行了模拟计算，得到了使总费用最低的三聚甲醛精制工艺的联合操作参数。模拟计算结果成功地指导了小试操作，并可为大型工程设计提供可靠的基础数据。     

测定环境中钚的新方法

提出了ＴＯＰＯ萃取，大面积有机相制原与平行板屏栅电离室α谱仪结合，测定草、土壤等环境中钚的新方法。土壤和草灰的化学回收率分别为７２％和９７％，最低探测限为４×１０＾－２Ｂｑ／ｋｇ。分析了Ｉ－ＡＥＡ和ＮＩＳＴ的标准物质，结果与标准值相符。操作程序简单、快速，适用于核事故应急分析和环境监测。     

反应精馏法制备高纯度醋酸甲酯

在中试反应精馏塔中以浓硫酸为催化剂进行了醋酸与甲醇反应制备醋酸甲酯的试验。反应精馏塔的精馏段为填料,反应段为立体催化精馏塔板,采用连续操作,考察了回流比、甲醇进料位置、停留时间、催化剂用量对反应精馏的影响。试验结果表明,当回流比为1.2、甲醇进料位置为第11～15块塔板、停留时间为2.2～2.5h、催化剂与醋酸的质量比为1.07∶100时,塔顶醋酸甲酯的质量分数达到99.50%以上,醋酸的转化率达到99.85%以上。     

500kW以下发电机组常见励磁故障及处理

通过对500kW以下水轮发电机励磁系统使用中常见典型故障结合实际进行深度分析,提出处理方法和整改措施.     

电流模精密整流电路

由电压型运算放大器组成的精密整流电路要严格地匹配电阻才能获得精密全波整流波形．本文给出一种具有CCⅡ电路特性由运算放大器AD844所构成的电流模精密整流电路．无需匹配电阻就可输出良好的精密全波整流波形．且具有输入电压范围大，频带宽等特点．