聚邻苯二胺膜电极的性能及其对苯醌还原动力学的影响

利用循环伏安法和原位红外反射光谱法研究了pH=7.0的磷酸盐缓冲溶液中聚邻苯二胺(PPD)膜电极的电化学行为。在比0.0V(SCE)负的电位区,PPD呈现氧化还原活性,氧化还原过程伴有H₂PO₄^-离子的嵌入和脱出,证明聚合物带有正电荷。苯醌在该膜电极上的还原反应发生在PPI)的电化学活性电位区内。旋转圆盘电极实验表明,苯配可渗入膜内并与聚合物交换电子。根据PPD为导电聚合物的模型分析了膜电极上苯配还原的动力学并讨论了对其影响的因素。     

Hidden in plain sight: unlocking the full potential of cyclic voltammetry with the thin-film rotating (ring) disk electrode studies for the investigation of oxygen reduction reaction electrocatalysts

Cyclic voltammetry conducted with a thin-film rotating disk electrode, or ring-disk electrode (CV-TF-R(R)DE) is a very popular ‘ex situ’ tool for the rapid screening of electrocatalysts for their activity in oxygen reduction reaction. Despite its popularity and broad use, in most instances only a small part of the information that could be accessed by CV-TF-R(R)DE is actually used by scientists in their research. This work outlines both innovative and more traditional (but half-forgotten) ways of using CV-TF-R(R)DE to its optimal or full potential in the ongoing quest to study the most relevant features of oxygen reduction reaction electrocatalysts and quickly identify the most promising candidates for their applications in fuel cells or other electrochemical devices.     

Mn3+/Mn2+氧化还原体系的旋转圆盘电极法性能

氧化还原液流电池的独特性能受到关注[1～4]。本文综合运用循环伏安法,旋转圆盘电极法研究锰离子浓度较高(0 25～0 35mol·L-1、转速范围较宽(400～4200rpm)、同时考虑过电位的条件下Mn(Ⅲ)/Mn(Ⅱ)电对在RDE铂盘电极上的电极过程动力学并确定有关的动力学参数,了解其影响因素,为该电对作为氧化还原液流电池正极活性材料提供动力学依据。1　实验部分铂电极使用前在铬酸洗液中浸10min,水冲洗干净,蒸馏水淋洗,然后在6 3mol·L-1H2SO4中超声清洗10min,再用CHI660电化学工作站(美国CH仪器公司)控制,以0 05V/s的扫速在-1 0～1 2V之间扫…     

A fast tissue stiffness-dependent elastography for HIFU-induced lesions inspection

To monitor HIFU-induced lesion with elastography in quasi-real time, a fast correlation based elastographic algorithm using tissue stiffness–dependent displacement estimation (SdDE) is developed in this paper. The high time efficiency of the proposed method contributes to the reduction on both the number of the displacement points and the computational time of most of the points by utilizing local uniformity of the tissue under HIFU treatment. To obtain admirable comprehensive performance, the key algorithm parameter, a threshold to densify the displacement points, is optimized with simulation over a wedge-inclusion tissue model by compromising the axial resolution (AR) and the computational cost. With the optimum parameter, results from both simulations and phantom experiments show that the SdDE is faster in about one order of magnitude than the traditional correlation based algorithm. At the same time, other performance parameters, such as the signal-to-noise ratio (SNRe), the contrast-to-noise ratio (CNRe) and the axial resolution (AR), are superior to or comparable with that obtained from the traditional algorithm. In vitro experiments on bovine livers validate the improvement on the time efficiency under the circumstances of real tissue and real radio frequency (RF) signal. This preliminary work implies potential of the SdDE in dynamic or close real time guidance and monitoring of HIFU treatment.