Application of PVD coatings for developing a DSA-type anode

Preliminary studies were conducted to develop a dimensionally stable anode (DSA) electrode prepared by reactive sputtering method. The microstructure, surface morphology and electrochemical properties of iridium oxide (IrO₂) coatings synthesized by unbalanced magnetron sputtering (UBMS) and conventional DSA electrode were compared. In addition, the possibilities of IrO₂ films synthesized by UMB on a real DSA electrode were investigated by electro-chemical application test. The degree of non-stoichiometry and surface area were closely related to the electro-chemical activity of the IrO₂ electrode. The feasibility of making a DSA electrode prepared by PVD technique was demonstrated through the present work.     

Effects of chronic estradiol treatment on delayed spatial alternation and differential reinforcement of low rates of responding.

Estrogens have been shown to both enhance and impair cognitive function depending on several factors, including regimen of hormone treatment, age of subject, and task attributes. In rodent models, estradiol tends to enhance spatial learning and impair response or cued learning, but effects on executive functions are less well-studied. In this experiment, spatial working memory and response inhibition were tested using delayed spatial alternation (DSA) and differential reinforcement of low rates of responding (DRL) tasks in ovariectomized rats that were given chronic estradiol via Silastic implants resulting in serum estradiol concentrations of 86.2 ± 8.2 (SEM) pg/ml. Rats were tested for 25 days DSA with variable delays of 0, 3, 6, 9, and 18 seconds between lever presentations, followed by 30 days on a DRL-15s operant schedule. Estradiol-replaced rats showed a significantly lower proportion of correct responses on the DSA task compared to vehicle-implanted ovariectomized animals. On DRL, estradiol-treated rats showed a lower ratio of reinforced to nonreinforced presses. These data suggest that chronic estrogen exposure may impair rats' abilities on measures of executive function including working memory and response inhibition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

DSA Tools在电力系统小扰动稳定安全评估中的应用

为分析可再生能源并网中可能出现的电力系统小扰动稳定性问题,采用小扰动稳定性动态评估的方法,提出基于DSA Tools实现小扰动稳定性的综合评估。通过采用特征值分析、故障分析、单机无限大系统扫描和小扰动稳定性极限搜索等方法,对IEEE14节点系统和IEEE145节点系统的小扰动稳定性进行分析。研究结果表明IEEE14节点系统小扰动稳定性较好,IEEE145小扰动稳定性则较差。另外,研究表明DSA Tools软件和SSAT分析工具可应用于电力系统预警方案设计和系统保护框架策略的优化。     

基于KNN的DSA图像去噪及GPU的快速实现

为快速地去除或减少DSA(Digital Subtraction Angiography)图像的噪声,对比评价KNN(K Nearest Neighbors)算法对高斯噪声、泊松噪声、斑点噪声、椒盐噪声4种噪声去除或减少的效果,帮助医生快速准确地为病人诊断疾病.提出的算法主要贡献在于构建了基于GPU(Graphics Processing Unit)的加速方法,使传统图像去噪的运算速度得到大幅提升.基于图像降质、图像还原过程建模,使用KNN算法对4种噪声去除或减少,并对算法做并行化处理,利用GPU加速实现去噪的过程.通过实验得出,KNN算法能较好地去除或减少高斯噪声、泊松噪声来还原DSA图像,使用CUDA(Compute Unified Device Architecture)编写可在GPU上运行的程序,利用GPU对1 024×1 024像素的24位深度的DSA图像去噪,平均渲染帧率能达到190.53 f/s(帧/秒),较传统CPU(Central Processing Unit)串行,平均处理速度提高70.86倍.使用GPU加速能够快速地处理数据量较大、计算密集的DSA噪声图像,实现有效并且快速的高斯噪声去除,帮助医生精、准、快地诊断疾病.     

Effect of nitrogen content on dynamic strain ageing behaviour of type 316LN austenitic stainless steel during tensile deformation

Abstract

The effect of nitrogen content on the dynamic strain ageing (DSA) behaviour of type 316LN austenitic stainless steel has been studied. The nitrogen content was varied from 0·07 to 0·22 wt-%. The tensile tests were carried out over a temperature range of 300–1123 K and at three strain rates in the range 3×10^?3–3×10^?5 s^?1. Serration was observed in the load elongation curves in the intermediate test temperature range and has been considered due to DSA phenomenon. The critical strain to onset of serrated flow increased with increase in nitrogen content and strain rate. The temperature for onset of DSA and the temperature of disappearance of DSA were found to increase with the increase in nitrogen content. The variations in tensile strength and work hardening rate of the steel with temperature exhibit peak values in the intermediate temperature range and have been attributed due to DSA phenomenon. The activation energy for DSA, estimated based on the temperature and strain rate dependences of the strain to onset of serrated flow, was found to increase from 111 to 218 kJ mol^?1 with the increase in nitrogen content from 0·07 to 0·22 wt-% and the increase has been attributed to the possible enhanced interaction of the DSA causing interstitial nitrogen with substitutional chromium.     

电催化氧化处理化工污水技术现状及进展

电催化氧化技术作为一种高级氧化技术,是目前污水处理技术发展的重点方向之一.介绍了电催化氧化技术的基本原理,如阳极氧化、阴极还原;重点论述了阴阳极催化材料的研究现状和进展,对钛基DSA电极的发展动态做了详细阐述.     

钛基DSA阳极在电镀铬工艺中的应用研究

通过Hull槽电解、电化学特性和长期稳定性测试的方法研究了DSA (IrO₂,Ta₂O₅),DSA (IrO₂,Pt) 阳极和PbSn合金阳极在电镀铬溶液中的性能,并进行对比分析。结果表明,钛基DSA阳极真实活性比表面远远大于其几何表面;在镀铬溶液中表现出较低的析氧电位和较好的电催化活性,尤其是DSA (IrO₂,Pt) 阳极在高电流密度下表现出更好的电催化活性;但是由于溶液中的F^-添加剂侵蚀Ti基体使得钛基涂层阳极在镀铬溶液中的稳定性和寿命均比PbSn合金阳极短。     

电芬顿降解活性艳红X3B的阳极影响因素

以钛基氧化锡纳米涂层(DSA)电极作为阳极,以活性炭纤维(ACF)作为阴极,与石墨板(GE)电极进行组合,形成三组不同的电极对,用于比较研究电芬顿反应中的阳极影响因素。降解模拟染料活性艳红X3B,其脱色率和矿化率均为:电极体系a(阴极/ACF,阳极/DSA)>b(阴极/ACF,阳极/GE)>c(阴极/GE,阳极/DSA)。其中最优电极体系a反应90 min完全脱色,180 min内矿化率和平均电流效率分别为75.3% 和56.7%。XRD和SEM表征表明:DSA电极和ACF电极在电芬顿反应中具有稳定的化学结构。循环伏安扫描的结果表明三组电极体系均无明显的阳极直接氧化反应发生。采用荧光法检测了活性氧化物种,发现三组电极体系生成羟基自由基的数量与其降解效果完全一致。本研究证明DSA 对于电芬顿反应有促进作用,并且这一促进作用是通过催化H₂O₂生成·OH 这一间接途径来实现的。     

稀土Gd掺杂对SnO2电催化电极性能影响的研究

采用浸渍法、溶胶-凝胶法,以SnCl4·5H2O、Sb2O3、Gd(NO3)3为前驱体,制备了稀土Gd掺杂SnO2涂层电极及SnO2电极.以苯酚为目标有机物,研究了不同稀土掺杂量、不同制备方法所获得电极的电化学降解特性,确定了较适宜的稀土掺杂量和制备方法.在本实验条件,稀土掺杂量(原子质量比)为SnSbGd=10061条件下制备的电催化电极性能最好,溶胶-凝胶法制备的电极其电催化性能及稳定性能均优于浸渍法制备的电极.对所制备的稀土Gd掺杂电极及空白电极进行了TOC测试、UV扫描分析及SEM、XRD、XPS等表征,分析并讨论了稀土掺杂对SnO2电极性能的影响机理.结果表明,稀土Gd的掺杂有利于SnO2电极电催化性能的提高,而且不同稀土掺杂量对SnO2电极性能影响并不相同.     

Ir-Ta氧化物涂层阳极在硫酸盐电解溶液中的电化学行为

采用测量极化曲线等电化学方法研究了钛基Ir-Ta氧化物涂层阳极在酸性硫酸盐溶液中的电化学行为。结果表明:酸性硫酸盐溶液中Ir-Ta氧化物涂层阳极上的析氧反应发生电化学极化,但超电势远低于Pb阳极和Pb-Ag阳极而电催化活性好,可以显著降低电解能耗。溶液pH和电解温度升高,Ir-Ta氧化物涂层阳极上析氧反应的超电势降低;溶液中含有不同金属离子时析氧反应的超电势略有不同,但金属离子浓度不影响其超电势。Ir-Ta氧化物涂层阳极在1 mol/L H2SO4溶液和电流密度40000A/m2的条件下的强化寿命可达55天。