Load-settlement behaviour of a strip footing resting on iron ore tailings as a structural fill

This study presents a laboratory investigation of load-settlement behaviour of a strip footing resting on iron ore tailings used as a structural fill.The footing was placed at various depths in the tailings bed.The relative density of the tailings was varied as D_r = 50%,70%and 90%.An incremental load was applied on the footing while observing the settlement until the failure took place.The results obtained for tailings were compared with those for the sandy soil.It is observed that the load-bearing capacity and stiffness increase with an increase in footing embedment depth and relative density.Compared to load-settlement behaviour of Perth sandy soil,the tailings fill could have as high as 22 times and 13.5 times the load-bearing capacity and stiffness,respectively.Therefore,the replacement of sandy soil with iron ore tailings for structural fills is cost-effective,and moreover,this application contributes to environmental sustainability in construction.     

Properties of lightweight expanded polystyrene aggregate concretes containing fly ash

Lightweight concretes can be produced by replacing the normal aggregates in concrete or mortar either partially or fully, depending upon the requirements of density and strength levels. The present study covers the use of expanded polystyrene (EPS) beads as lightweight aggregate, both in concrete and mortar. The main aim of this programme is to study the mechanical properties of EPS concretes containing fly ash and compare the results with these in literature on concretes containing OPC alone as the binder. The effects of EPS aggregate on the green and hardened state characteristics of concretes containing fly ash were evaluated. The compressive strength of the EPS concretes containing fly ash show a continuous gain even up to 90 days, unlike that reported for OPC in literature. It was also found that the failure of these concretes both in compression and split tension was gradual as was observed earlier for the concretes containing plastic shredded aggregates. The stress-strain relations and the corresponding elastic modulus were also investigated.     

铸造冒口CAD设计模块的研究开发

分析研究了冒口补缩机理和设计方法，根据设计资料和工厂生产实际，将ＭＦＣ与ＡＲＸ结合，开发出了实用型铸造工艺ＣＡＤ冒口设计模块，该模块既是ＩｎｔｅＣａｓｔＣＡＤ的一个主要功能模块，又可作为一上独立的软件运行，同时提供了友好的用户界面和独立的数据操作技术，显著提高了冒口设计的效率和准确度，具有广阔的应用前景。     

Surface Brillouin scattering studies on vanadium carbide

Vanadium carbides in a range of carbon to metal ratio were investigated by surface Brillouin scattering (SBS) on the (100) and (110) surfaces. The surface acoustic wave (SAW) velocity varies with the crystal surface and direction and displays an approximately linear increase with the carbon to metal ratio. The tensor elastic constants of the samples were extracted and, while they vary significantly from the different carbon to metal ratio, the value of anisotropy ratio remains close to 0.8 for all samples. The directional dependence of the Young's modulus and shear modulus are obtained from the tensor elastic constants. In the directions chosen, both Young's modulus and the shear modulus reduce with decreasing carbon to metal ratio, with this behaviour being directionally dependent.     

白炭黑原位复合聚丙烯酰胺水凝胶的流变行为与次级网络

采用水溶液聚合法以过硫酸钾为引发剂,丙烯酰胺为主要单体,聚乙二醇双丙烯酸酯为交联剂,与不同类型和不同添加量的白炭黑原位复合,合成制备出交联型和线型的两类复合聚丙烯酰胺凝胶,并获得了在50 000 mg/L的高矿化度盐水中吸水30倍后弹性模量达100 Pa以上的聚丙烯酰胺水凝胶.采用高级流变仪证实了白炭黑与聚丙烯酰胺形成的次级网络的存在,通过对比不同类型白炭黑和不同白炭黑填充量对聚丙烯酰胺水凝胶流变性能的影响,发现白炭黑填充形成的次级交联网络对聚丙烯酰胺水凝胶的模量和损耗角正切的影响规律,通过与合成的无化学交联的白炭黑原位复合聚丙烯酰胺模型化合物对比和FTIR分析,揭示了白炭黑次级网络对水凝胶的增强机理.     

用最佳三角逼近刻画Orlicz-Besov空间

定义了一类新的Ｏｒｌｉｃｚ－Ｂｅｓｏｖ空间并用ｎ阶三角最佳逼近阶对其性态进行了刻画。     

行波法在10kV铁路自闭/贯通线故障测距中的应用

作者介绍了输电线路行波法测距的原理,概述了铁路自闭/贯通线路的特点及其故障测距的研究现状,研究并分析了行波法在自闭/贯通线测距中应用的特殊性,即自闭/贯通线的线路结构、供电方式及负荷的影响,提出了将零模和线模分量相结合,用零模分量对故障点反射波和对端母线反射波进行识别,用线模分量进行测距的方法.并用PSCAD/EMTDC对其进行了建模及仿真分析.仿真结果表明,所提出的方法是可行的.     

竹木复合材料托盘力学性能的研究

通过对普通胶合板托盘、一层竹芯板托盘和三层竹芯板托盘进行抗弯试验,分析了在3种载荷情况(5、10和15)下,三种类型的托盘所需要厚度的最小值.发现一层竹芯板的结构可以明显降低厚度,能够节约材料,降低成本;同时还得出了厚度和载荷经验公式.     

一种新的基于自适应步长的二级CMA盲接收机

在高速数据传输的频率选择性信道的直接序列扩频系统中,基于恒模算法（CMA）的二级盲接收机能够在只知道期望用户的扩频码以及定时信息的情况下进行自适应联合均衡和多用户检测,具有较好的实时处理性能。但是其第一级检测器的自适应求取采用的是递归最小二乘（RLS）算法,该算法在收敛稳定性等方面具有一系列缺陷,从而对整个算法的性能造成了损害。本文将戴彧虹 袁亚湘自适应步长迭代算法作为第一级检测器的自适应处理方式,并给出了新的方案的完整实现流程。理论和仿真结果显示,经过改进后的二级CMA盲自适应接收机比起原先的算法有着更低的误码率和更高的稳态输出信干比（SINR）,在总体性能上有了很大提高。      

一种新的混合自适应盲均衡器

提出了一种基于QAM信号的新的混合自适应盲均衡算法。结合了MCMA算法以及AMA算法的优点,通过设置自适应遗忘因子λ,用来自适应加权两类独立代价函数,一类是MCMA的代价函数,另一类是AMA的代价函数。通过搭建QAM盲均衡系统平台,仿真结果表明,提出的算法相比于CMA、MCMA和CMA/AMA算法,有效地降低了稳态误差和误码率,并具有良好的收敛速度,大大提高了系统的性能。