Catalytic reduction of no over perovskite-type catalysts

In the present work, we have investigated the reduction of NO by propane over perovskite-type oxides prepared by malic acid method. The catalysts were modified to enhance the activity by substitution of metal into A or B site of perovskite oxides. In addition, the reaction conditions, such as temperature, O₂ concentration, and space velocity have been varied to understand their effects on the catalytic performance. In the LaCoO₃ type catalyst, the partial substitution of Ba and Sr into A site enhanced the catalytic activity in the reduction of NO. For the La_0.6Ba (Sr)_o.4 Co_1−x Fe_xO₃ (x=0-1.0) catalyst, the partial substitution of Fe into B site enhanced the conversion of NO, but excess amount of Fe decreased the conversion of NO. The surface area and catalytic activity of perovskite catalysts prepared by malic acid method showed higher values than those of solid reaction method. The conversion of NO increased with increasing O₂ concentration and contact time. The introduction of water into reactant feed decreased the catalytic activity but the deactivation was shown to be reversible over La_0.6Ba_0.4Co_1−x ,Fe_xO₃ catalyst.     

大型矿车用减速机齿轮系统的疲劳分析

提出一种基于"放大因子"、采用二维平面单元模拟三维实体动态工况的计算疲劳的方法,对某矿车减速机齿轮系统进行疲劳分析,得到太阳轮、行星轮和扭力管在不同抗拉强度下的疲劳寿命.结果表明:太阳轮和扭力管最易发生疲劳破坏;齿轮寿命对抗拉强度的依赖性较敏感;得出的齿轮系统热处理后的抗拉强度建议值能为设计提供参考,且该方法能大大提高计算效率.     

齿轮泵挤出技术在橡塑行业的应用与发展

简要介绍了齿轮泵的结构、性能及工作原理，从齿轮泵挤出机的发展，齿轮泵挤出系统向压延机喂料，齿轮泵与MCTD挤出机相结合三个方面，讲述了其在橡塑行业中应用的优越性及缺憾。     

Pt-V2O5-WO3/TiO2 catalysts supported on SiC filter for NO reduction at low temperature

The catalytic filter, V₂O₅-WO₃-TiO₂ supported on a ceramic filter, is known as a promising material for treating particulates and NO _x simultaneously at optimum temperatures around 320°C. In order to improve its catalytic activity at low temperatures, the effect of Pt addition on the catalytic filter has been investigated. Catalytic filters, Pt-V₂O₅-WO₃-TiO₂/SiC, were prepared by co-impregnation of Pt, V, and W precursors on TiO₂ coated-SiC filter by vacuum aided-dip coating. The Pt-added catalytic filter shifted the optimum working temperature from 280–330°C (for the non Pt-impregnated filter) to 180–230°C, providing N _x slip concentration less than 20 ppm for the treatment of 700 ppm NO at a face velocity of 2 cm/s with the same value over the non Pt-added catalytic filters. The promotional effect following the addition of Pt is believed to result from electrical modification of the catalyst maintaining a high electron transfer state. Ammonia oxidation was also observed to be dominant above the optimal temperature for SCR.     

复合金属氧化物脱硫剂还原法再生机理

利用热天平测试了ＣＯ、Ｈ２还原饱和脱硫剂微孔内Ｆｅ２（ＳＯ４）３的起始反应温度及还原速率，用Ｘ射线衍射法分析了反应中间产物及最终产物．实验结果表明，脱硫剂还原法再生的反应温度较传统热分解法低约２００℃，ＣＯ作再生脱硫剂的还原气体优于Ｈ２，ＣＯ还原脱硫剂内Ｆｅ２（ＳＯ４）３的反应级数为０．８７，活化能为１４２．９ｋＪ／ｍｏｌ．     

改性聚醚醚酮复合材料在齿轮上的应用

用液晶聚合物（TLCP）、碳纤维（CF）、铜粉、MoS2等添加剂对聚醚醚酮（PEEK)进行改性，制备了改性PEEK复合材料，讨论了各添加剂对改性PEEK性能的影响，并用来制造发动机机油泵齿轮。结果表明，用TLCP、CF等改性的PEEK可提高PEEK的强度和耐磨性，并改善加工性，该复合材料能满足机油泵类齿轮的使用要求。     

回转窑传动齿圈振动分析及处理方法

回转窑传动系统主要由电动机、减速机、大齿圈和小齿轮组成。因回转窑属大型重载高温设备，其大齿圈易发生振动等故障而影响窑的正常运行。作者详细分析了回转窑齿圈振动的产生原因，并介绍了对应的解决处理方法。中铝股份山西分公司的生产实践表明，这些针对性的措施，均能有效地解决大齿圈的振动问题，从而保证了回转窑的正常运转。     

基于分辨函数的极大团搜索算法

寻找极大团是几何图论极为重要的基础研究问题之一。将分辨函数模型与极大团性质结合,定义了顶点的极大团分辨函数、顶点关于某顶点子集的布尔映射函数,得到了一些与极大团相关的重要性质与定理,证明了图的极大团搜索问题可快捷自然地转换为相对简单的分辨函数表达式约束,为设计极大团搜索算法提供了一种有效的理论依据与求解途径。进而引入约简树构造方法设计了基于分辨函数的极大团搜索算法,最后通过给定无向连通图实例说明了算法的可行性与有效性。     

链图的概念格表示

概念格是基于对象集和属性集之间的二元关系建立的一种层次结构。它与极大二部团存在着一定的联系。将概念格属性约简理论应用于链图,首先给出了链图的概念格表示,其次证明了二部图G=(V1,V2,E)是链图,当且仅当G′=(V1,V2,E)是链图,这里(V1,V2,E)是(V1,V2,E)的约简形式背景。     

我国节能减排的现状、问题与解决路径-一个文献综述

我国的节能减排问题日趋突出。本文从文献梳理角度对我国节能减排的现状、存在的问题以及解决路径进行了述评。研究显示,我国节能减排潜力巨大,节能减排效率低下。直接原因是由于我国产业结构、外贸结构、FDI 结构以及技术结构不合理造成的,但其背后更深层次的原因主要体现在：（1）GDP锦标赛下政治晋升制度的不合理导致了环境的负外部性;（2）激励与约束机制不完善导致政府缺乏节能减排的动力;（3）分税制的不完善导致了我国产业结构的不合理。为此,我们需要从优化产业结构、调整外贸结构、弱化 FDI的“污染避难所”效应以及增强技术进步效应入手,通过改革 GDP 锦标赛下政治晋升制度、完善激励与约束机制、调整财税体制等途径解决我国节能减排问题。