焙烧铁尾矿制备透水砖试验研究

为了改善尾矿制砖的力学性质，解决尾矿堆积问题，采用焙烧铁尾矿、水泥和粉煤灰为胶凝材料，2.36~4.75 mm粒级铁尾矿为粗骨料，通过搅拌、成型和养护工艺制备透水砖，探究了焙烧铁尾矿用量、水胶比、目标孔隙率和振动时间对透水砖性能的影响，对比未焙烧尾矿制备透水砖的性能。结果表明：① 焙烧尾矿制备透水砖最佳试验条件为：焙烧尾矿掺量60%，振动时间40 s、水胶比0.3，目标孔隙率20%；此时，透水砖抗折强度为3.34 MPa，符合国家标准Rf3.0，抗压强度为15.44 MPa，符合国家标准MU15，透水系数为2.58×10-2 cm/s，符合国家标准A级标准，实测孔隙率为23.41%。② 焙烧尾矿掺量为60%时效果最佳；未焙烧尾矿掺量为50%时效果最佳，抗折、抗压强度分别为3.38 MPa和14.54 MPa，透水系数符合国家A级标准；焙烧尾矿比未焙烧尾矿多替代水泥10%的情况下，力学性能焙烧尾矿透水砖较好，而透水性能则未焙烧尾矿透水砖较好。     

EMAP: An efficient mutual authentication protocol for passive RFID tags

Radio frequency identification (RFID) system is a contactless automatic identification system, which uses small and low cost RFID tags. The primary problem of current security and privacy preserving schemes is that, in order to identify only one single tag, these schemes require a linear computational complexity on the server side. We propose an efficient mutual authentication protocol for passive RFID tags that provides confidentiality, untraceability, mutual authentication, and efficiency. The proposed protocol shifts the heavy burden of asymmetric encryption and decryption operations on the more powerful server side and only leaves lightweight hash operation on tag side. It is also efficient in terms of time complexity, space complexity, and communication cost, which are very important for practical large-scale RFID applications.     

iMapReduce: A Distributed Computing Framework for Iterative Computation

Iterative computation is pervasive in many applications such as data mining, web ranking, graph analysis, online social network analysis, and so on. These iterative applications typically involve massive data sets containing millions or billions of data records. This poses demand of distributed computing frameworks for processing massive data sets on a cluster of machines. MapReduce is an example of such a framework. However, MapReduce lacks built-in support for iterative process that requires to parse data sets iteratively. Besides specifying MapReduce jobs, users have to write a driver program that submits a series of jobs and performs convergence testing at the client. This paper presents iMapReduce, a distributed framework that supports iterative processing. iMapReduce allows users to specify the iterative computation with the separated map and reduce functions, and provides the support of automatic iterative processing within a single job. More importantly, iMapReduce significantly improves the performance of iterative implementations by (1) reducing the overhead of creating new MapReduce jobs repeatedly, (2) eliminating the shuffling of static data, and (3) allowing asynchronous execution of map tasks. We implement an iMapReduce prototype based on Apache Hadoop, and show that iMapReduce can achieve up to 5 times speedup over Hadoop for implementing iterative algorithms.     

浅析影响汽车轮毂跳动的几个因素

汽车轮毂的跳动是一个非常重要的性能尺寸，它影响着汽车运行的平稳性及安全性。论文从理论上简单地分析影响轮毂跳动的五个环节，同时对影响轮毂跳动较大的环节进行试验分析，并运用统计过程控制的方法进行了验证。     

高性能环氧乙烯基酯树脂在车辆制造上的应用

介绍了几种特种环氧乙烯基酯树脂在不同类型车辆部件制造上的应用，阐述了高性能树脂基复合材料在车辆上的应用情况和发展趋势。     

中国腈纶行业的发展现状与展望

通过对近几年中国腈纶的表观需求、生产能力和进出口情况进行了综合分析,阐述了影响中国腈纶行业的发展因素,并根据当今的发展现状提出了腈纶行业面对机遇和挑战的发展策略。     

Mg:Ce:Fe:LiNbO3晶体生长及其全息存储性能

在同成分LiNbO3(LN)中,掺入MgO的摩尔分数分别为0,2%,4%,6%,掺入(质量分数)0.1?O2和0.08?2O3,采用提拉法生长了优质的Mg:Ce:Fe:LN晶体.检测了Mg:Ce:Fe:LN晶体的红外透射光谱和光损伤阈值.结果表明:6%Mg:0.1?:0.08?:LN晶体的OH-振动吸收峰紫移到3 532cm-1,其光损伤阈值比Ce:Fe:LN晶体提高2个数量级以上.用二波耦合光路测试晶体的衍射效率,写入时间和擦除时间.计算了光折变灵敏度和动态范围.结果表明:Mg:Ce:Fe:LN晶体全息存储性能优于Fe:LN晶体和Ce:Fe:LN晶体.以4%Mg:0.1?:0.08?:LN晶体作为全息记录材料,实现了总存储页面为3 200幅图像的存储,再现图像清晰完整.     

虚拟机软件结合LoadRunner的一种测试方案探讨

基于虚拟化技术进行软件自动化测试是测试主流技术发展的一个方向。介绍了虚拟机软件VMware结合测试工具软件LoadRunner的一种软件测试方案,详细介绍了测试方法、测试环境、测试用例以及数据处理方法。通过对同一B/S系统在真实环境和虚拟环境中进行对比性能测试,并基于实测数据加以分析,论证了该方案的优越性,得出了能否应用的结论。     

校园隐性文化建设问题探究

校园隐性文化建设是校园文化建设的要害和难点,它通过校园环境渗透到师生的思想之中,影响着他们的行为。在进行校园隐性文化研究中,首先要探讨校园隐性文化建设的基本条件,才能寻求到研究对策,顺利开展校园隐性文化建设,进而营造一个良好的校园文化。     

基于多维筛分类器的可视化帕金森病诊断

针对目前基于模式识别的语音障碍帕金森病诊断可解释性差、可推广性差的问题,本文提出基于多维筛分类器的可视化帕金森病诊断。该分类器具有全程可视化的特点,在保证诊断精度的同时,可以将特征进行可视化表示。可视化的引入不但使操作者了解不同特征对于诊断的重要性,而且可以发现最具诊断价值的特征,有助于简化帕金森病的诊断过程并提高诊断水平。