助成胶作用和氧化镧掺杂对活性氧化铝热稳定性的影响

研究水溶液成胶制备氧化铝过程中,掺杂氧化镧及利用聚乙二醇助成胶对氧化铝热稳定性和比表面的影响。通过XRD表征手段和TG检测方法来检测氧化铝在不同温度焙烧后的晶相改变和热失重情况,并利用BET检测方法检测不同温度焙烧后的比表面。实验结果表明,氧化镧的掺杂可提高氧化铝的热稳定性,利用聚乙二醇助成胶可有效提高氧化铝的比表面。     

Packet Queueing Delay in Resilient Packet Ring Network Nodes

The packet queueing delay is one of the most important performance measures of a data network and is also a significant factor to be considered in the scheduling buffer design for a network node. This paper presents a traffic queueing model for resilient packet ring (RPR) networks and a method for quantitatively analyzing queueing delays in RPR nodes. The method was used to calculate the average queueing delays of different priority traffic for different transit queue modes. The simulations show that, in the transmit direction, lower priority traffic is delayed more than higher priority traffic, and that Class-A traffic is delayed more in a single-queue ring than in a dual-queue ring. In the transit direction, the secondary transit buffer in the dual-queue ring contributes more to the traffic delay than the primary transit buffer in the single-queue ring, which in turn causes more delay than the primary transit buffer in the dual-queue ring.     

基于“互联网+”视角的民办高校核心竞争力培养

互联网+模式有利于促进民办高校教学模式变革,整合民办高校教学资源,优化民办高校价值链,便于高校领导利用师生碎片化时间进行管理。因此,应通过建立智慧校园、资源优化平台、学生自主管理平台、网上绩效评估系统和互联网+图书馆等措施,提升民办高校核心竞争力。     

内部审计如何提高审计报告质量

内部审计出具的审计报告是企业内部审计部门实施审计后，对被审计单位的财务收支的真实、合法、效益发表审计意见的书面文件，是审计工作成果的集中体现。审计报告质量是审计工作质量的决定性因素，但笔者在审理审计报告过程中发现，当前内部审计人员出具的审计报告还存在一些不可忽视的问题。     

中国科学技术馆

中国科技馆新馆位于北京奥林匹克公园内，与著名的“鸟巢”、“水立方”遥相呼应，总建筑面积10．2万平方米，建设总投资近20亿元人民币，展示面积超过4万平方米，2009年9月16日全面建成开放。     

机械CAD教学探讨

本文探讨在CAI环境下，应用计算机三维设计软件的造型技术，加强对工科生三维造型设计能力的培养。介绍在高校，《机械CAD》教学实践的体会。     

工科高校培养创新思维的流体力学设计性实验竞赛

分析了传统流体力学教学实践模式存在的问题,提出了一种能激发学生学习热情、培养学生创新思维的新的教学方法,即开展设计性流体力学实验竞赛。实践证明,该方法简单易行、成本低廉,并且能让学生真正参与到实践中来,有助于培养学生各方面能力,教学效果显著。该方法为工科高校力学专业的基础课教学提供了重要参考。     

Modeling and Experimental Study of PEM Fuel Cell Transient Response for Automotive Applications

This paper presents an analysis of the dynamic response of a low pressure proton exchange membrane (PEM) fuel cell stack to step changes in load, which are characteristic of automotive fuel cell system applications. The goal is a better understanding of the electrical and electrochemical processes when accounting for the characteristic cell voltage response during transients. The analysis and experiment are based on a low pressure 5 kW proton exchange membrane fuel cell (PEMFC) stack, which is similar to those used in several of Tsinghua's fuel cell buses. The experimental results provide an effective improvement reference for the power train control scheme of the fuel cell buses in Olympic demonstration in Beijing 2008.     

线路型避雷器在110kV输电线路中的应用分析

本文就线路型避雷器防雷的基本原珲及其选点进行了详细的分析,提出了线路型避雷器在使用过程中应该注意的问题.