Catalytic Combustion of Lean Methane Assisted by Electric Field over Pd/Co<Subscript>3</Subscript>O<Subscript>4</Subscript> Catalysts at Low Temperature

A series of Pd/Co₃O₄ catalysts were prepared by Self-Propagating High-Temperature Synthesis (SHS) method in this study, and electric field was applied for catalytic combustion of lean methane over Pd/Co₃O₄ catalysts at low temperature. When electric field was applied, the catalytic combustion performance of Pd/Co₃O₄ catalysts was greatly improved, and the application of electric field could reduce the load of active element Pd to some extent while maintaining the same efficiency. Based on experimental tests and the analysis results of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), H₂-temperature-programmed reduction (H₂-TPR) and in-situ diffuse reflectance infrared Fourier transform spectroscopy (in-situ DRIFTS), the mechanism of catalytic oxidation of CH₄ over Pd/Co₃O₄ catalysts in electric field was proposed. The catalytic combustion of CH₄ occurs only when the temperature is higher than 250 °C normally, but when electric field was applied, the whole process of CH₄ oxidation was promoted significantly and the reaction temperature was reduced. Electric field could promote the reduction of the support Co₃O₄ to release the lattice oxygen, resulting in the increase of PdO_x and the surface chemisorbed oxygen, which could provide more active sites for the low-temperature oxidation of CH₄. Furthermore, electric field could accelerate the dehydroxylation of CoOOH to further enhance the activity of the catalysts.     

滚石碰撞冲击数值模拟分析

随着山区道路与隧道的发展与广泛应用,隧道进出口上部岩体发生掉块、落石的情形时有发生。该类落石对隧道进出口与道路安全的影响日益成为严重安全问题。然后现有关于落石冲击的研究中,冲击计算主要以半经验半理论为主,然而各类算法的适宜性、合理性一直未能得到充分验证。文中通过理论分析结合三维数值模拟对落石的冲击力算法及其落石尺寸、自由落高和缓冲土层厚度等指标的相关性进行了研究,得到了关于落石冲击力计算的有益结果。     

TRAFFIC-BASED SCHEDULING MECHANISM IN AN IP/ATM ROUTER

Introduction　　 In recentyears,ATM has been installed com-prehensively,especially in the backbone of cam-puses and cities. On account of the differencesamong ATM,IP and other networks[1,2 ] ,how toeffectively integrate them is a very important andcritical issue to ATM and other networks.An IP/ATM router which can interconnect1 55M ATM,1 0 0 M Ethernet,2 M ATM,PPP,2 B D ISDN and X.2 5is under developing in ourlab.In prior work,we have designed its softwarearchitecture[3] .We als…     

新型装配式挡土墙稳定性影响因素敏感度分析

新型装配式挡土墙相比于传统重力式挡土墙有自重小、地基承载力要求低、适应性强、用料节省、施工时间短等优势,且可实现节能、节水、节材和环保的目的,是挡土墙设计研究的重要方向.相对于传统重力式挡土墙,装配式挡土墙需要更多地考虑墙体自重的减小、装配结构的拼接等导致的变形及稳定性问题,因此重点对装配式挡土墙稳定性问题进行了探讨.首先在对传统重力式挡土墙稳定性研究的基础上,以倾斜式墙背挡土墙为例,按照规范规定计算了挡土墙的相关安全系数;继而利用敏感度分析的方法,逐个分析了墙中填料的容重、墙后填土内摩擦角和墙背倾角在新型装配式挡土墙稳定性中所起的作用;最后分析了各因素对挡土墙稳定性的影响程度,找出了影响挡土墙稳定性的主要因素,并提出了新型装配式斜墙背挡土墙设计中应当注意的各种问题,为新型装配式挡土墙的设计提供了一定的依据.     

低压平行集束导线在农村配电网改造中的应用

本文综述了低压平行集束导线国内外研究及应用现状,介绍了当前我国使用低压平行导线模式的标准、电气性能技术参数。实际应用中平行集束导线供电模式在降低工程造价、降低线损、减少末端电压降等方面具有显著的经济效益,在我国农网低压改造中应用广泛。     

武汉地区路灯中压专网系统“专改公”应用研究——以武汉经济开发区为例

本文阐述了武汉地区路灯中压专网供电系统现状,指出了路灯中压专网系统存在的问题,分析了武汉地区路灯中压供电系统"专改公"的优势。并结合实际情况,对武汉地区路灯中压专网系统"专改公"进行了技术设计和论证,提出了可行的解决方案。     

寻梦北疆

开车去新疆，一直都是一个梦想，从阴山、祁连山、阳关，出玉门关一直到新疆，用车轮丈量过的梦，是怎样的充满神秘与诱惑呢？期待着上路……     

装卸设备点检制在二连站的应用实践

二连站装卸作业所根据本所装卸设备多、口岸换装作业量大的实际,在装卸设备的运用维护管理中试行点检制,制定出点检作业标准及运行管理制度,对设备运行状态进行动态分析,提高了设备管理水平。     

梦回草原——蒙古国探秘

贴平车贴,分发手台,我们的车队又要出发。习惯了清晨、朝阳,以及大多熟悉的笑容,一起去蒙古国探寻戈壁的神奇、发现沙漠的秘密、体味草原的细腻、感受异乡都市的古朴。