Atomistic insight into the hydration and proton conducting mechanisms of the cobalt doped Ruddlesden-Popper structure Sr3Fe2O7-δ

Sr₃Fe₂O_7-δ (SFO) with two-layer Ruddlesden-Popper (R–P) structure has recently been proved to be a promising material for the single phase cathode in proton conducting solid oxide fuel cells (P–SOFCs). To investigate the hydration reactions and proton conducting mechanisms of SFO and cobalt doped SFO (SFCO), both bulk and surface properties were calculated. We conclude that R–P structures have advantages in P–SOFCs. The unique Sr–O–M layer can facilitate the hydration process. Although in Sr–O–F and Sr–O–N layers, it is difficult for the formation and migration of oxygen vacancies, protons are most stable. Furthermore, cobalt doping can not only improve the electronic conductivity but also enhance surface properties of SFCO. The easily exposed Co–Fe–O surface can also facilitate the hydration reactions on the surface. Our work could give an informative insight into the relationships among the doped elements, the R–P structures, the hydration process and the proton conducting properties.     

Effect of focused ion beam sample preparation on the phase composition of zirconia

The investigation of phase transformations in metastable ceramic systems such as zirconia often requires local phase analysis within the areas of interest. Electron backscatter diffraction is a suitable method in combination with focused ion beam sample preparation. The interaction between ion beam and sample has to be carefully considered. In case of metastable Y-PSZ and Mg-PSZ, phase transformations were observed after FIB preparation with 30?kV, 30?nA and 5° incidence angle. Damage was the dominating effect for angles of 72°. The expected local temperature increase due to the ion bombardment with 30?kV and 30?nA is 700?K for ZrO₂. Thus, the observed phase transformations can be explained on the basis of the temperature increase in the corresponding Y-PSZ phase diagram. In case of Mg-PSZ, the transition temperature is 1083?°C. The local temperature increase was obviously lower. The excitation energy for the observed phase transformation was smaller than expected from the phase diagrams of the thermodynamic equilibrium. Using 5?kV, 4.8?nA and 5° incidence angle, no phase transformations and no damage were observed. Thus, these conditions are well suited for the FIB preparation of metastable zirconia.     

A Distribution‐freeCUSUMChart for Monitoring Variability of AutocorrelatedProcesses

We present a distribution‐free tabular cumulative sum chart for monitoring the variability of an autocorrelated process. A quantity known as the asymptotic variance parameter is employed as a measure of the variability, and a distribution‐free tabular cumulative sum chart is applied to variance estimates calculated from batches of nonoverlapping samples. The proposed chart is applicable to a stationary process with a general marginal distribution and a general autocorrelation structure. It also determines control limits analytically without trial‐and‐error simulations. The performance of the proposed chart is tested on stationary processes with both normal and nonnormal marginals with various autocorrelation structures. Copyright © 2014 John Wiley & Sons, Ltd.     

一类两性分枝过程条件均值增长率的极限性质

本文主要研究随机环境中配对依赖人口数两性 Galton-Watson 分枝过程的条件均值增长率的极限性质．利用上可加函数的性质，得到配对单元平均增长率的极限性质和该过程条件均值的上界和下界．文中给出了关于过程条件均值增长率的两个序列，利用配对单元平均增长率的性质，获得了这两个序列的极限性质．随机环境中配对依赖人口数两性分枝过程比较复杂，本文的结论推广了现有的研究成果．     

煤化工酸水汽提装置运行存在问题及解决方法

本文简述了酸水汽提工艺的发展概况和技术进展,详细介绍了煤化工酸水汽提装置实际运行中存在的几类主要问题,并提出切实可行的解决措施,具有一定的借鉴意义。     

重力坝模型的尺寸效应

利用两个不同比尺预制缝重力坝模型的试验成果，以有限元富集技术进行非线性断裂分析，建立了极限承载力和长度比尺的确定性尺寸效应公式。混凝土重力坝的断裂尺寸效应满足指数衰减关系，用三次指数衰减公式可以准确地预测原型的极限承载力。断裂过程区的相对长度是引起模型试验尺寸效应的主要原因。数值计算结果表明，断裂过程区相对长度不仅是与材料有关的参数，能否充分发展还取决于结构尺寸和几何形状；断裂过程区相对长度的尺寸效应不同于统计尺寸效应和断裂参数尺寸效应，具有尺寸范围效应。断裂过程区相对长度在小试件、大试件和相对无穷大试件的发展程度不同。     

以IBAC为核心处理洗浴废水的试验研究

根据洗浴废水的水质特征,采用原水→混凝沉淀-过滤→固定化生物活性炭(Immobilized Biological Activated Carbon,IBAC)→微滤膜(MF)→UV消毒→出水的工艺流程.混凝沉淀-过滤物化预处理单元可以有效地减少洗浴废水中的各类污染物.IBAC生化处理单元,实现有机污染物、LAS、浴臭等有效去除,是保证出水合格的根本措施.微滤膜发挥物理截留作用、UV消毒杀死细菌和总大肠菌群.出水水质达到＜城市供水水质标准＞(CJ/T 206-2005).     

太原精神病院污水处理系统改建为中水处理系统的工程设计

太原精神病医院将现有生活污水处理系统改建为中水回用系统,平均日处理水量100 m3.工程设计充分考虑了对原有设施的利用,生物处理单元采用生物接触氧化法.为减少污水提升次数,调节池设在生物处理单元之后.通过延长水力停留时间缓解水量、水质波动对沉淀、生物处理单元的不利影响,投入运行后效果良好.     

Al2O3陶瓷激光铣削试验研究

采用Nd∶YAG脉冲激光器对Al2 O3陶瓷进行铣削加工试验。系统研究了工艺参数对铣削量和铣削面质量的影响规律 ,并利用优化的铣削工艺对Al2 O3陶瓷进行多种形状的铣削加工。     

简化形式的系统EMC预测分析技术概述

本文探讨了系统级简化形式的电磁兼容性预测分析方法，该方法对于只有几对发-收干扰对的系统EMI的预测分析简洁有效，它避免了大系统间繁复的建模与大量的数据采集及其计算工作，从而对于只考虑其结果的系统间的EMC预测分析提高了效率。