粉煤灰及养护龄期对湿拌砂浆性能的影响

以粉煤灰取代部分水泥,研究其掺量及养护龄期对保水率、收缩率、稠度、粘接强度和力学性能的影响,并利用X射线荧光光谱分析仪(XRF)和扫描电子显微镜(SEM)对粉煤灰的物理化学性质进行分析.试验结果表明:掺量在0％ ～ 40％,随着粉煤灰掺量的增加,湿拌砂浆干缩率呈减小趋势,湿拌砂浆保水率呈减小趋势.粉煤灰的掺入量与湿拌砂浆拌合物的稠度正比例关系,随着粉煤灰掺量的增加而增大.湿拌砂浆14d粘接强度随着粉煤灰掺量的增加呈下降趋势.在试验室条件下,掺粉煤灰砂浆试块抗压强度随着养护时间的增长不断增大.因此,在湿拌砂浆中掺入低于30％的粉煤灰时,可以在满足湿拌砂浆力学性能的前提下,抑制收缩变形,提高粘接强度.     

The production and practice of cold-rolled steel sheets for automobile

Shougang Group has carried out a strategic structure adjustment in order to realize the promise of Chinese people to the Olympic Games.Automotive sheets are chosen as a type of strategic product and an engine to upgrade enterprise management,technology and operation to reach the top international level during the transition from long products to steel sheets in Shougang Group.Since 2006,Shougang Group has made an elaborate preparation on steel sheet culture,production line construction,technology import,pilot plant and talent reserve.It lays the foundation for the development of automotive sheets.The developing history of cold rolled automotive sheets is reviewed and the research and development of cold rolled automotive sheets, tackling key problem of defect on surface and the latest progress of automotive sheets construction are described in this paper.The main contents were given as follows:①The products of automotive sheets realize zero breakthrough in Shougang Group.Monthly output was 300 ton in January,2009 and it increased to 48 000 ton in June,2010.The ratio of IF steel sheets increases to 70%from 40%.The proportion of outside panel in automotive sheets occupys more than 15%.②A high emulational pilot plant is used as a product developing platform to develop successfully automotive sheets with 1 000 MPa and below.It guarantees that the industrial development of DP and TRIP sheets gets success at a time.It covers continuous annealing sheets with tensile strength≤780 MPa and galvanizing sheets with tensile strength≤590 MPa.③Individual design is used to meet special requirement of customer.Shougang owns 23 inner brands of LCAK and IF steels.It insures that the grades of yield strength cover whole range from 120 to 270 MPa.It keeps the stabilization of steel performance by means of chemical composition control and high accuracy rolling technology.For example,the strength of soft steel fluctuates within±15 MPa.④The steel sheets with surface grade O5 are produced steadily by solving forming striation of IF steel,grain coarse on surface,edge curling skin and mountains - and - waters painting defects.⑤The safeguard mechanism on quality of products is improved steadily and the output of automotive sheets and outside panel increases greatly by building consistency quality management system、information - system and customer service system.     

基于结构一致和特征学习的网页信息标签提取

网页信息指网页的正文、标题、发布时间、媒体等,每个信息都存在于HTML文档特定的标签中,自动获取这些标签可以实现在相同模板下的网页信息自动提取,对于大规模抓取网页内容有很大帮助。由于在相同模板下不同网页之间结构一致,网页信息有一定统计特征,提出了一种基于结构对比和特征学习的网页信息标签自动提取算法。该算法包含三个步骤：网页对比、内容识别和标签提取。在51个模块下对1?620个网页进行测试,实验结果表明,通过提取标签获取网页信息不仅速度快,而且抓取的内容更加准确。     

最近最远得分的聚类性能评价指标

聚类算法是数据分析中广泛使用的方法之一,而类别数往往是决定聚类算法性能的关键。目前,大部分聚类算法需要预先给定类别数,在很多情况下,很难根据数据集的先验知识获得有效的类别数。因此,为了获得数据集的类别数,本文基于最近邻一致性和最远邻相异性的准则,提出了一种最近最远得分评价指标,并在此基础上提出了一种自动确定类别数的聚类算法。实验结果证明了所提评价指标在确定类别数时的有效性和可行性。     

Soft measurement of pulp suspension flow velocity based on wavelet transform

A soft measurement technique is presented, which the pulp suspension flow velocity (PSFV) can be obtained by analysis of pulp fibre consistency signal without using the flow sensor or flow meter. Doppler Effect in pulp fibre consistency signal, which is caused by the relative motion between pulp suspension flowing in pulp pipe and consistency sensor fixed in the pipe, is discovered on the basis of studying the structure of pulp suspension and the properties of pulp fibre consistency signal, and it is proved by wavelet transform (WT) in this paper. WT are used to analyse pulp fibre consistency signal based on Doppler Effect. PSFV can be determined by the average period of WT which is used to analyse pulp fibre consistency signal based on Doppler Effect. The corresponding tests indicate that the measurement technique is feasible with high precision and better dynamic characteristics.     

分布式存储环境下CAx模型的一致性策略

现有分布式存储环境在维护主、副本的一致性时,无法避免冗余的副本建立或更新,在存储较大且无法对副本进行局部更新的CAx模型时,主、副节点之间的网络带宽浪费严重,为解决该问题,提出了一种一致性策略。该策略能够跟踪主本的变化,当且仅当副本被访问且与主本不相同时,副本才会被更新。基于有限自动机和自动机乘积,给出了策略的形式化定义。通过分析状态图,确定策略是完备的和安全的,并给出了策略的技术实现。最后,通过实例证明了该策略的有效性。     

仿真结果距离检验方法和频谱分析方法对比分析

针对仿真结果动态一致性检验,将距离检验方法与频谱分析方法进行对比分析。研究表明,目前常用的频谱分析方法需要将数据从时域转化到频域后再对仿真结果动态一致性进行检验,而数据从时域转化到频域后,已不能反映样本序列中各时刻值的先后顺序,也就无法检验实测样本序列和仿真样本序列之间各时刻值先后顺序关系的一致性,因此,频谱分析方法只适用于可以忽略序列中各时刻值先后顺序的平稳序列。但是,工程实际中样本序列各时刻值的先后顺序也是需要检验的重要参数,譬如先爬升再下降与先下降再爬升这两种导弹弹道是截然不同的,频谱分析方法不能对此进行有效的检验。距离检验方法则能直接在时域内对仿真结果动态一致性进行定量检验,它对平稳序列和非平稳序列均适用,可有效地解决仿真结果动态一致性定量检验的问题。     

多芯锂离子电池组的一致性与安全性

分析了多芯锂离子电池组一致性包含的开路电位、内阻、容量等因素,通过实验验证了一致性对串联和混联电池组产生过压充电和欠压放电的影响,发现一致性差会影响电池组的安全性。通过电芯筛选和电路监测,可消除一致性带来的安全隐患。     

电力系统时域仿真的动态一致性检验

电力系统中模型参数的辨识值常因优化算法、收敛区间、迭代次数等的差异而不同,此时常规的误差分析方法很难判断并选择合理的参数组。为解决这一问题,文中提出采用一种定量的不确定性分析方法——随机响应面法对仿真结果进行动态一致性检验的新观点,并提出了相应的检验标准。由于随机响应面法能克服传统的蒙特卡洛法仿真次数多、时间长的缺点,利用随机响应面法可快速计算出参数组中多个参数的联合不确定度,从而得到仿真结果的均值和置信区间,校验模型参数的有效性,为参数的合理选择提供参考依据。某大区电网的负荷实测记录验证了该方法的有效性。     

微电子封装中的喷射点胶过程建模和控制

针对喷射点胶阀存在点胶一致性差的问题,提出了一种基于体积估计模型的批次PI控制策略。通过对胶体流变特性进行分析,基于胶体剪切应力和剪切速率关系建立了喷射点胶的流量模型,依此推导出体积估计模型。基于建立的模型,运用批次PI算法来实现喷射点胶阀的一致性控制。仿真和实验结果验证了体积估计模型的可靠性,并表明该控制方法能有效地改善喷射点胶的一致性。