非线性地基上桩结构物空间分析

本文提出了桩结构物－非线性地基空间相互作用分析的迭代法和非线性有限元法。其中，桩基分析用ｐ－ｙ曲线法。结合实际结构物进行了大量的计算及比较分析，成果是令人满意的，可以付诸应用。     

ARM架构下Turbo译码时延性能研究

为了适应基于5G的物联网技术的快速发展,以ARM架构作为物联网终端设备的构想具有重要的实际应用意义。但ARM架构能否满足5G物联网终端性能要求仍然不明确,特别是终端对于海量数据的处理时延将直接影响其实际可行性。鉴于此,基于开源的空中接口平台(OAI),本文重点研究了采用ARM架构的Turbo译码时延问题,并与x86架构计算机进行对比。测试结果表明,基于ARM架构的译码延时要比基于x86架构的译码延时长20%～25%,鉴于两种架构性能上的差异,这一延时差距符合预期。     

Molecular dynamics simulation of mechanical properties of Ni–Al nanowires

We employed molecular dynamics simulations to study mechanical properties of Ni–Al nanowires by calculating the stress–strain response of the wires under various loading conditions. For this purpose, nanowires were subjected to uniaxial strain at different strain rates and temperatures using embedded atom model potential. The behaviour of the wires at lower and higher strain rates was investigated, and the yield and rupture strain values and also Young’s Modulus were obtained which are essential factors for the ductility of the wires. This work indicates that how the stress–strain response of the nanowires are affected by varying strain rates and temperatures.     

Syntactic foams from copolymers based on epoxidized soybean oil

Syntactic foams are been increasingly used as core of sandwich panels due to their light weight and good mechanical properties. This investigation evaluates the compressive, flexural and thermo-mechanical properties of syntactic foams made by embedding randomly dispersed hollow glass microspheres in bio-based resins obtained by partial substitution of diglycidyl ether of bisphenol A (DGEBA) with epoxidized soybean oil (ESO). Volume fraction of glass microballoons was 0.55 in all foam formulation. Flexural and compressive strength values decreased simultaneously with increasing ESO content. Similar trend was observed for the flexural and compressive modulus and glass transition temperature. The work further showed that mechanism of failure mainly depended on the fracture of microballoons regardless the ESO content in the formulation. Results reported herein suggest that large fractions of DGEBA can be replaced by ESO with minor effect on mechanical and thermal properties.     

Bond–slip on CFRP/GFRP-to-concrete joints subjected to moisture,salt fog and temperature cycles

Research on bond between composite and concrete on beams externally reinforced with fiber reinforced polymers (ERBs) has generated many publications, but uncertainties remain. The issue of the long term behavior of those joints, especially the effect that severe and prolonged environmental actions may induce, justifies the search for additional data and recommendations to avoid premature debonding and failures.The present paper devotes attention to the effects of environmental aging on the constitutive bond-slip curves. Aging was imposed on an accelerated manner and several actions used to degrade the behavior of the joints evaluated by mechanical testing.Prismatic blocks of reinforced concrete linked on the upper side by a stainless steel hinge and externally bonded by a continuous strip of carbon or glass fiber reinforced polymer (CFRP or GFRP) adherent to the soffit were made so as to fit in commercially available laboratory climatic chambers. After aging, they were tested till failure under four point loading.Aging conditions imposed on the CFRP beams were (i) cycles of high-low relative humidity, (ii) salt fog cycles, and, on the GFRP beams, (iii) salt fog cycles, (iv) dry/wet cycles (water with 5.0% weight of NaCl), (v) total immersion in salt water, and (vi) freeze/thaw cycles.The results of the experimental program enabled the proposal of bond-slip laws that take into account the aging of the beams. They also showed that salt fog cycles were more severe in the case of CFRP, while freeze/thaw cycles were more degrading on bond of GFRP-to-concrete. The salt water effects on the GFRP beams appeared to be beneficial, most likely by improving the tensile strength of concrete. Numerical modeling certified by the obtained experimental data is presented that allows more general estimates of the environmental effects.     

武汉市二七沿江商务区楼房爆破拆除塌落振动分析

为了分析高层建(构)筑物爆破拆除时塌落造成的地面振动的特征及对周边建筑物的影响大小,对武汉市二七沿江商务区19栋楼房爆破拆除中的地面振动进行了测量,并对监测点实测的数据爆破与塌落振动速度、卓越频率、傅里叶谱及反应谱特性进行分析。结果表明:高层建筑物爆破拆除中塌落振动比爆破振动影响更大,频率更低;1#楼周边为已拆除废弃空旷场地、减振措施较少,塌落振动水平分量高于竖向分量;常用的塌落振动估算公式可以更好地描述竖向振动分量,而无法描述本次幅值更大的水平分量;持续时间随距离的增加而变长;反应谱在高频段高于设计谱,但由于周边无建筑物,不会造成危害。     

共存阴离子对核酸阻锈剂在模拟混凝土孔溶液中钢筋阻锈作用的影响

将一种含有长度在20～80个碱基的各种引物的混合溶液溶解在核酸缓冲液中作为核酸阻锈剂,通过线性极化和电化学阻抗谱(EIS)两种电化学手段分别研究共存阴离子HCO_3~-和SO_4~(2-)对核酸阻锈剂在模拟混凝土孔溶液中对钢筋氯盐腐蚀的影响。利用X射线光电子能谱(XPS)分析了在有共存阴离子存在的模拟混凝土孔溶液中钢筋电极在核酸阻锈剂作用下表面膜的组成结构。结果表明:核酸阻锈剂具有良好的钢筋防腐蚀效果,共存阴离子HCO_3~-的存在使钢筋的腐蚀速率加快,但核酸的加入能明显减弱钢筋腐蚀倾向,具有和商用阻锈剂(主要成分为磷酸钠)基本相同的阻锈效率;共存阴离子SO_4~(2-)的存在加快了钢筋的腐蚀速率,且SO_4~(2-)的浓度较低时核酸阻锈剂的阻锈效率已经超过了同等条件下的商用阻锈剂。     

人工湿地工矿业废渣基质对氨氮的吸附研究

通过钛渣、钢渣和炉渣对氨氮的吸附试验,比较分析了3种人工湿地基质对氨氮的吸附特征,探讨了影响基质对氨氮吸附性能的主要因素.结果表明,Langmuir方程描述3种基质的吸附特性比Freundlich方程更为精确,其中钢渣对氨氮的饱和吸附量最大.钢渣和钛渣对氨氮的吸附类型为物理吸附和化学吸附,炉渣对氨氮的吸附类型为物理吸附. 3种基质对氨氮的去除率都会随着投放量的增加而增大,但当投放量增加到一定量时,去除率不再随投放量变化;pH值的变化对3种基质吸附氨氮的性能分别存在一个阈值,无论是高于或低于这个阈值,吸附性能都会减弱.     

基于面向对象的电力系统中长期负荷预测软件的开发

为了更方便、快捷、准确地进行中长期负荷预测,开发了基于Windows的电力系统中长期负荷预测软件。软件采用面向对象程序设计方法,使系统易扩充、易维护。该软件除具有一般负荷预测软件所具有的计算快速、模型库丰富等特点之外,还有原始数据输入简单方便、模型库扩充简易、具备饱和负荷预测以及考虑了与其它常用软件的接口等独特的地方。以华东某地区的供电量历史数据为例,选择了5种不同模型进行预测,并对结果进行了分析和比较,最后还对该地区进行了“s”型饱和负荷预测。分析表明该软件使用方便,预测精度满足电力负荷预测的精度要求,具有一定的实用性。     

多目标配电网故障定位的Pareto进化算法

提出一种用于配电网故障定位的多目标优化模型,采用带精英策略的快速非支配排序遗传算法(NSGA-Ⅱ)进行求解.传统多目标优化问题通过加权方式转换为单目标问题,对权值比较敏感,且每次只能得到一种权值下的最优解.NSGA-Ⅱ则避免了传统加权求解时权值的选择和解的偏好性.该算法采用快速非支配排序机制,计算复杂性低;同时考虑个体拥挤距离,从而保证种群的多样性;最后,提出适用于故障定位的最优解集处理方法,便于从多目标最优解集中筛选出唯一符合故障情况的解.算例测试分别模拟单点、多点故障,以及信息完备和部分信息畸变的情况,测试结果表明,所提方法均能准确地定位故障区段.