NiCoFe/C cathode electrocatalysts for direct ethanol fuel cells

A direct ethanol fuel cell (DEFC), which is less prone to ethanol crossover, is reported. The cell consists of PtRu/C catalyst as the anode, Nafion^® 117 membrane, and Ni–Co–Fe (NCF) composite catalyst as the cathode. The NCF catalyst was synthesized by mixing Ni, Co, and Fe complexes into a polymer matrix (melamine-formaldehyde resins), followed by heating the mixture at 800 °C under inert atmosphere. TEM and EDX experiments suggest that the NCF catalyst has alloy structures of Ni, Co and Fe. The catalytic activity of the NCF catalyst for the oxygen reduction reaction (ORR) was compared with that of commercially available Pt/C (CAP) catalyst at different ethanol concentrations. The decrease in open circuit voltage (V_oc) of the DEFC equipped with the NCF catalysts was less than that of CAP catalyst at higher ethanol concentrations. The NCF catalyst was less prone to ethanol oxidation at cathode even when ethanol crossover occurred through the Nafion^®117 film, which prevents voltage drop at the cathode. However, the CAP catalyst did oxidize ethanol at the cathode and caused a decrease in voltage at higher ethanol concentrations.     

个旧有色冶化公司一期低浓度铜烟气制酸工程简介

介绍90 kt/a铜冶炼烟气制酸装置的设计和运行情况。采用三段式净化工艺与污水处理系统相结合, 有效地解决了用高砷、氟铜精砂生产硫酸的问题。采用多孔板支撑缩放管气体换热器与高蓄热能力的转化器相结合,在转化器进口平均φ(SO2)约4％,而生产负荷仅为设计能力(270t/d)的74％的条件下,转化系统仍能维持自热平衡。     

一种支持企业集成的基于Agent的企业信息模型

文章从企业集成的角度,对企业信息模型进行探讨和研究,提出基于Agent的企业信息模型以支持企业集成和电子商务活动.     

抛物问题Mortar有限元的瀑布型多重网格法

对抛物问题的全离散格式采用Mortar型有限元逼近,构造了相应的瀑布型多重网格法,证明了该方法的最优性.     

非线性等式与不等式问题的信赖域算法

５１．引言 本文讨论如下非线性等式与不等式问题的求解问题：其中,吐。）是＊”＋Ｂ的连续可微函数． 非线性问题（１．１）广泛出现于优化问题、互补问题及变分不等式等应用数学领域中,因而对其算法的研究也是计算数学的一个重要部分．许多作者考察了该问题的求解,如Ｄｅｎｎｉｓ和Ｓｃｈｎａｂｅ［６］, Ｐｓｈｅｎｉｃｈｌｌｙｉ［９］, Ｒｏｂｉｎｓｏｎ［１０１等人讨论了该问题的牛顿法求解,梯度法求解,Ｂｕｒｋｅ和 Ｈａｎ［‘］讨论了高斯一牛顿法求解． Ｄｅｎｎｉｓ在［５］中首次采用了信赖域算法的求解,［５］中通过引…     

用自回归最小二乘消噪法提纯轴承故障信号

为了消除噪声信息、提取反映机械部件故障的有用信息，对自适应消噪方法进行研究。利用自回归最小二乘消噪方法提纯反映轴承故障的机械信号，该方法应用于6215轴承故障的检测，提取出反映轴承故障的冲击信号，检测出其轴承外圈和滚珠故障，并与理论计算的轴承故障特征频率相吻合，效果很好。     

Cutting Force Model for a Small-diameter Helical Milling Cutter

In the milling process, the major flank wear land area (two-dimensional measurement for the wear) of a small-diameter milling cutter, as wear standard, can reflect actual changes of the wear land of the cutter. By analyzing the wearing characteristics of the cutter, a cutting force model based on the major flank wear land area is established. Characteristic parameters such as pressure parameter and friction parameter are calculated by substituting tested data into their corresponding equations. The cutting force model for the helical milling cutter is validated by experiments. The computational and experimental results show that the cutting force model is almost consistent with the actual cutting conditions. Thus, the cutting force model established in the research can provide a theoretical foundation for monitoring the condition of a milling process that uses a small-diameter helical milling cutter.     

油管缺陷在线检测仪的研究

文中研究了油管局部缺陷和壁厚减薄缺陷的漏磁场检测原理。研制了一种新型的井口式油管缺陷检测仪,缺陷检测传感器的组合式探头具有自动张合、浮动和随动功能,能够满足油管在线检测对检测传感器的要求。仪器可用在井口对油管进行在线连续定量检测,检测结果不受管表面的油泥或其它非导磁性材料的影响。测试表明,该仪器具有精度和分辨率高,结构简单,安装方便,性能可靠等优点。     

求解一类变分不等式离散问题的迭代法

本文提出了求解变分不等式离散问题的一个迭代算法,并在合理的假设下证明了算法的单调收敛性．