碳纤维水泥基材料的温阻效应及其测试方法

对碳纤维水泥基材料（CFRC）进行的两极法和四极法的对比测试研究表明，两种方法都能得到稳定的电阻值；但两极法的测试结果包含了测试电极的电阻和电极与CFRC材料之间的接触电阻，难以准确反映CFRC材料的真实电阻值；采用四极法测试可消除电极电阻和接触电阻．同时还研究了不同碳纤维掺量（0．4％和1．O％）的CFRC材料的温阻效应．结果表明，在-10-60℃的温度范围内，CFRC材料的电阻率随温度的升高而减小，灵敏度随着碳纤维掺量的增加而减小．     

碳纤维机敏混凝土梁弹性应力自监测实验研究

基于碳纤维混凝土材料的压力机敏性,采用两电极法研究了CFRC梁构件弹性应力自监测的规律．循环荷载实验结果表明,试验梁受压区CFRC弹性应力状态开始变化时,其电阻变化率存在滞后反应现象,但在随后的应力状态变化过程中该滞后反应消失,且电阻变化率与弹性压应变基本保持一定的线性相关关系．测试结果具有良好的可重复性．基于实验所得CFRC电阻变化率与弹性压应变的相关曲线,可实现碳纤维机敏混凝土梁控制截面的弹性应力自监测．     

水泥基材料损伤自诊断机理声发射研究

采用声发射与电阻技术对碳纤维混水泥基材料土在单轴受压和三点弯曲负荷下内部损伤进行了监测 .研究表明 ,在三点弯曲负荷下 ,碳纤维混凝土的荷载 -挠度曲线与试件的电阻和声发射事件数存在良好的对应关系 .对于碳纤维水泥基复合材料 ,其导电率主要依赖分散于水泥基体中相互搭接的碳纤维的渗流网络 .材料内部的损伤引起相互搭接的渗流网络破坏 ,而致使材料电阻增大 .因此 ,在整个加载过程中 ,体系的电阻反映了材料内部的损伤 .另一方面 ,通过声发射信号的分析 ,可以鉴定材料内部损伤的机理 .     

基于车辆超载预警系统的导电混凝土导电性能研究

通过正交实验设计，进行了基于车辆超载预警系统的不同导电材料掺量比条件下导电混凝土导电性能探究.实验结果表明：1.2 MPa荷载以内，导电性能随着荷载的增大而增强，但增强趋势逐步衰减；通过压敏性分析，得出钢纤维体积分数0.15%、石墨体积分数1.00%、碳纤维体积分数0.35%、硅灰质量分数3.50%为导电材料的最佳掺量比；4种导电材料对导电混凝土压敏性和电阻的影响由强到弱分别为钢纤维、硅灰、石墨、碳纤维和硅灰、钢纤维、碳纤维、石墨；随着碾压次数的增多，试件的压敏性降低而压力敏感特性趋于稳定，第4次实验后压敏性下降3.5%,电流-荷载曲线均呈现先增大后减小的趋势.     

镁质粉煤灰复合胶凝材料试验

目的研究不同原材料掺量对复合胶凝材料试件强度的影响,选择最佳配合比制备一种新型的复合胶凝材料取代普通硅酸盐水泥.方法根据不同配合比参数,制备相应的复合胶凝材料试件,测试其抗折强度和抗压强度,研究轻烧镁粉掺量、硫酸镁溶液掺量、硫酸铝溶液掺量以及磷酸掺量对试件强度的影响.结果硫酸镁溶液质量分数不变时,试件的强度随轻烧镁粉掺量的增加而提高.轻烧镁粉与硫酸镁的质量比固定时,试件的强度随硫酸镁溶液浓度的降低而减小,且m(Mg O)∶m(Mg SO4)固定值为4.6时,试件的强度取得最大值.m(Mg O)∶m(Mg SO4)∶m(H2O)为4.6∶1∶3.7,硫酸铝溶液掺量、磷酸掺量分别为轻烧镁粉掺量的1.5%、1.8%时,复合胶凝材料试件28 d时的抗折强度、抗压强度取得最大值,分别为6.8 MPa、51.4 M Pa.结论制备的镁质粉煤灰复合胶凝材料的强度可达到同等42.5级普通硅酸盐水泥的强度要求.     

玄武岩织物增强水泥基复合材料拉伸力学性能

利用美特斯(MTS)万能试验机研究了掺入不同体积掺量(0、0.5%、1.0%、1.5%)短切碳纤维、玻璃纤维、钢纤维的2层和3层玄武岩纤维织物增强水泥基复合材料的拉伸力学性能.结果表明:短切碳纤维、玻璃纤维、钢纤维均可明显增加玄武岩纤维织物增强水泥基复合材料的开裂强度,并且存在最优体积掺量;在0~1.5%掺量范围内、2层织物时,开裂强度随着3种短纤维掺量的增加而增加,掺量1.5%时最大;3层织物时,开裂强度随着碳纤维、钢纤维掺量的增加先增加后减小,掺量1.0%时达到最大值,而随着玻璃纤维掺量的增加持续增加,掺量1.5%时最大.短切碳纤维、玻璃纤维不能增加其峰值荷载,而钢纤维则明显提高其峰值荷载,2层织物时最优掺量为1.5%,3层织物时最优掺量为0.5%.     

碱激发钢渣矿渣胶凝材料凝结硬化性能研究

通过对胶凝材料强度、水化热的测定和对水化产物种类及表观形貌的分析,探讨了缓凝剂和钢渣掺量对碱激发钢渣矿渣胶凝材料性能的影响,并对其水化特性进行了研究.结果表明:钢渣掺量为40%、矿渣掺量为60%时,外掺6%水玻璃激发剂和1%的K缓凝剂,所制得的胶凝材料的凝结时间和强度可以达到42.5R普通硅酸盐水泥的技术要求;碱激发钢渣矿渣胶凝材料的放热特性与碱激发矿渣胶凝材料类似,具有放热量小的特点;钢渣与矿渣组合有利于胶凝体系水化进程的发展,两者具有相互促进的作用.     

含粗骨料超高性能混凝土力学性能研究

针对超高性能混凝土(UHPC)胶凝材料用量大,前期成本高等问题,通过在UHPC体系中掺入粗骨料,用河砂代替石英砂,成功制备了具有优异力学性能的含粗骨料UHPC,并通过试验研究了粗骨料掺量以及钢纤维几何参数对含粗骨料UHPC力学性能的影响.结果表明:随着粗骨料掺量的增加(0~800kg/m3),UHPC抗压强度先增加后下降,静力受压弹性模量几乎呈线性增加;粗骨料掺量为0~400kg/m3时,UHPC抗弯拉强度和初裂强度变化较小,粗骨料掺量为400~800kg/m3时,UHPC抗弯拉强度和初裂强度明显下降;随着粗骨料掺量的增加(0~800kg/m3),UHPC弯拉荷载-挠度曲线变化明显,弯曲韧性明显下降,但均存在应变硬化过程;随着钢纤维长度增加,UHPC的抗压强度、抗弯拉强度以及弯曲韧性均增加,但是静力受压弹性模量和初裂强度变化较小.     

钢渣-水泥复合胶凝材料的水化放热和动力学研究

通过测定钢渣掺量（质量分数）分别为0、20%、30%、40%的水泥基复合胶凝材料的水化放热速率,根据Krstulovi?-Dabi?动力学模型得到几何晶体生长指数n、反应速率常数K、各阶段转换时的水化度α,进而研究钢渣掺量对钢渣水泥复合胶凝材料水化放热与动力学的影响。结果表明：随着钢渣掺量的增加,各阶段水化放热速率变化趋势不同,钢渣掺量30%和40%时,出现第3放热峰,水化放热量随着钢渣掺量的增加而降低;钢渣掺量0、20%、30%时,水化历程由结晶成核与晶体生长(NG)到相边界反应(I)再到扩散过程(D);钢渣掺量40%时,模拟曲线偏离实际水化速率曲线,水化过程不符合Krstulovi?-Dabi?动力学模型;钢渣掺量0~30%范围内KNG、KI、KD均随着钢渣掺量的增加而降低;相对于钢渣掺量20%试样而言,纯水泥与钢渣掺量30%试样的I过程水化度范围较大;钢渣掺量0~30%的试样,水化12h已经成型,然而相同条件下,钢渣掺量40%的试样仍然不能硬化成型。为避免水化速率过低,钢渣最大掺量应为30%。     

葡萄糖酸钠对胶凝砂砾石材料凝结时间及强度的影响

以葡萄糖酸钠作缓凝剂,测得掺量0.05%、0.1%、0.15%、0.2%、0.4%、0.6%、0.8%、1%、2%时胶凝砂砾石的初凝时间和终凝时间,以及3 d、7 d和28 d抗压强度,试验结果表明:在相同试验条件下,随着葡萄糖酸钠掺量的增加,胶凝砂砾石的初凝时间和终凝时间都有较明显的延长,掺量为2%时分别延长了20 h和37.5 h;葡萄糖酸钠的掺量在0.1%时对胶凝砂砾石的抗压强度有所提升,随着葡萄糖酸钠的增加,胶凝砂砾石早期抗压强度下降明显,且中后期抗压强度也有一定下降,得到葡萄糖酸钠的适宜掺量为水泥用量的0.1%~0.8%。     

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-     

Density Functional Theory for the Response of Periodic Systems to Electric Fields Based on the Vector Potential Approach

正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with