厂拌热再生改性沥青混合料的动态黏弹特性

为研究再生改性沥青混合料的动态黏弹特性,进行了沥青混合料性能试验(AMPT),分析了试验温度和荷载频率对再生混合料动态模量和相位角的影响规律,以及旧料掺量、再生剂和老化的作用效应,建立了动态模量主曲线.结果表明:随温度升高,不同荷载频率内,再生混合料动态模量趋于一致,而相位角呈不同的变化趋势,旧料掺量大于70%,相位角峰值消失;高温下再生混合料黏性表现充分,动态模量受加载频率影响较小;中低温时再生混合料相位角随荷载频率增大而减小,温度较高时先增大后减小,峰值及其对应的荷载频率小于新拌混合料,且随旧料掺量增加进一步减小;较宽频域内,再生混合料与新拌混合料动态模量趋于一致,与旧料掺量、再生剂及老化无关.     

玄武岩纤维沥青混合料动态蠕变试验

为研究玄武岩纤维对沥青混合料高温抗车辙的改善效果,采用UTM-25伺服式材料动态测试系统,对掺加与不掺加玄武岩纤维的AC-13,SMA-13不同级配沥青混合料,在40,50和60℃温度环境下进行动态蠕变试验,对比分析6种不同级配沥青混合料的动态蠕变曲线、流变次数等.试验结果表明:掺加玄武岩纤维后,混合料在相同作用次数下的永久应变减小,且沥青混合料达到蠕变破坏阶段的累计作用次数大于不掺加玄武岩纤维的沥青混合料;沥青混合料的流变次数随温度升高而降低,掺加玄武岩纤维后降低趋势变缓,且温度越高效果越明显.可见,掺加玄武岩纤维能有效提高沥青混合料的抗车辙性能.     

基于间接拉伸试验模式的沥青混合料动态模量研究

鉴于间接拉伸模式决定沥青混合料动态模量的重要意义,基于间接拉伸试验模式,采用目前我国常用的2种沥青混合料,发展沥青混合料间接拉伸试验动态模量的测定和分析方法。基于GPM测试模式,通过修正参数,修正二维平面应力假设和试件膨胀的影响,根据修正的应力和应变决定沥青混合料的间接拉伸动态模量。根据时-温转换原则,基于Hirsch模型估算混合料模量极大值,分别采用Global Aging模型和Arrhenius模型获得移位因子,通过数值优化建立了参考温度为20℃的2种常用沥青混合料动态模量主曲,得出了主曲线的Sigmoidal数学模型。根据对2种混合料的动态模量主曲线比较分析表明AC-20型沥青混合料对加载频率和对温度的依赖性都较低于AC-13C型混合料,尤其在低频段表现更为明显。     

不同纤维沥青混合料性能研究

选用玄武岩纤维、木质素纤维以及聚酯纤维对AC-13C、SMA-13沥青混合料展开研究.通过对三种纤维沥青混合料相关性能研究,确定路用性能改善效果最优的纤维及纤维的最佳掺量;通过对不同纤维AC-13C、SMA-13混合料进行矿料级配设计及马歇尔试验,确定不同纤维掺量时混合料的最佳油石比及最佳纤维掺量;通过对不同纤维在最佳掺量时AC-13C、SMA-13混合料进行高温抗车辙、低温抗开裂以及抗水毁等路用性能试验得出,AC-13C沥青混合料玄武岩纤维、木质素纤维、聚酯纤维最佳掺量分别为0.4%、0.4%、0.3%,SMA-13沥青混合料玄武岩纤维、木质素纤维、聚酯纤维最佳掺量分别为0.5%、0.4%、0.4%,三种纤维在最佳掺量时均能改善AC-13C、SMA-13沥青混合料的路用性能,其中玄武岩纤维改善效果最优.     

不同热氧老化环境下SBS改性沥青及其混合料性能研究

【目的】探寻沥青及沥青混合料逐渐老化对沥青路面路用性能的影响。【方法】对不同热氧老化环境下SBS(I-D)聚合物改性沥青的常规指标、流变性能及以其制备的AC-13C沥青混合料的高温稳定性、低温抗裂性、水稳定性及单轴压缩动态模量开展试验研究。【结果】随着热氧老化程度的不断加深,沥青黏韧性及抗塑性变形的能力逐渐降低,脆性逐渐增强;随着热储存时间的增加,沥青软化点、5℃延度和针入度先升高后降低,135℃黏度逐渐升高;随着热氧老化程度的不断加深,沥青混合料高温抗车辙能力逐渐提高,低温抗开裂及抗水损害能力逐渐降低;沥青混合料动态模量随着温度的升高而降低,随着热氧老化程度的加深及加载频率的增大而升高,但温度为35、50℃时其变化趋势有所改变。【结论】随着热氧老化程度的不断加深,沥青混合料高温性能得到改善,低温及水稳定性能降低,该研究成果在实际工程应用中具有一定的价值。     

干法苯乙烯-丁二烯-苯乙烯嵌段共聚物改性沥青玛蹄脂碎石混合料的动态力学性能

采用简单性能试验机测试苯乙烯-丁二烯-苯乙烯嵌段共聚物(SBS)占基质沥青质量分数分别为6%、 8%的干法SBS改性SMA-13型沥青玛蹄脂碎石混合料(SMA13)在不同试验温度、加载频率时的动态模量与相位角,并与常规的湿法SBS改性SMA13进行对比分析,建立各自的动态模量主曲线。结果表明：在低温5℃及常温20℃时,改性剂含量不同的干法SBS改性SMA13的动态模量差异较小,并且均比湿法SBS改性SMA13的动态模量小,表明干法SBS改性SMA13具有较好的低温柔性;在较高温度50、 60℃时,干法SBS改性SMA13的动态模量、弹性模量与黏性模量均比湿法SBS改性SMA13的大,说明干法SBS改性沥青的高温抗变形能力更强,高温稳定性更优。     

沥青混合料动态模量主曲线方法对比分析

为了更好地研究沥青混合料的动态特性,在4.4、21.1、37.8、54.4℃这4个试验温度下对沥青混合料进行简单性能试验(SPT),获得动态模量随加载频率的变化规律,然后基于时-温转换原理,采用WLF法和二次多项式法对数据进行非线性拟合,以此建立动态模量主曲线模型,并对两种方法进行分析。结果表明:1)相同试验温度下,沥青混合料动态模量随荷载加载频率增大而增大,相同加载频率下,沥青混合料动态模量随试验温度升高而降低,且试验温度越低时,加载频率的影响越显著;2)WLF法和二次多项式法均可拟合动态模量主曲线,拟合度分别为0.899和0.998。相较而言,二次多项式法能有效减少预测误差,主曲线模型拟合度和光滑程度更高,能够更准确地描述沥青混合料粘弹性动态响应的影响。     

延庆崇礼高速公路沥青混合料低温性能研究

为了合理推荐延庆崇礼高速公路路面面层低温性能优越的沥青混合料,首先选取三种沥青混合料（SMA-13、SUP-13、AC-13）,在同一SBS改性沥青条件下,通过室内试验方法研究了三种沥青混合料的低温开裂性能,然后基于以上所得低温性能优越沥青混合料,替换SBS改性沥青为环氧沥青,研究其低温性能变化。结果表明：延庆崇礼高速公路沥青路面面层在抵抗低温影响方面宜采用SMA-13沥青混合料,如果经济允许最好采用SMA-13环氧沥青混合料;且对于常年冬季平均最低温度低于-5℃的地区,都宜选用SMA-13沥青混合料作为沥青路面面层;而对于常年冬季平均温度高于15℃的地区,宜选用AC-13沥青混合料作为沥青路面面层。     

旧料掺量对温拌再生沥青混合料耐久性的影响分析

为了研究旧料掺量对温拌再生沥青混合料耐久性的影响,采用冻融劈裂与水损坏敏感试验(MIST)研究混合料抗水损害性能,采用半圆弯曲试验研究混合料抗裂性能,采用标准贯入试验(SPT)研究混合料动态模型变化趋势。结果表明:随着回收沥青路面材料(RAP)含量的增加,水处理后沥青混合料弹性模量比逐渐提高,水对弹性模量的衰减程度影响相对较低;混合料破坏时的耗散徐变应变能DCSEf先增加后减少,温拌再生沥青混合料中存在一个最佳的RAP含量;旧料的增加在一定程度上降低了沥青混合料的抗开裂能力,使混合料向脆化方向发展,当旧料掺量达到一定水平后,再生沥青混凝土的抗裂性能将不再降低;同等条件下,RAP掺量越大,再生混合料动态模量越大,混合料表现出更多的刚性,更趋于脆性,随着试验温度的提升,温拌再生沥青混合料的动态模量更多地显现出黏弹性特征;相同RAP含量时,热再生沥青混合料浸水后抗变形能力、抗裂能力及动态模量均高于同等条件下的温拌再生混合料;热再生条件下能融化RAP料表面旧沥青的数量比温拌条件时多,使混合料更密实,其体积特征的变化带来了性能的差异。     

抗车辙剂和SBS对热拌沥青混合料高温与低温性能的影响

车辙和开裂是沥青路面的主要病害形式,采用外加剂改善沥青路面的高温与低温性能是防治车辙和开裂的主要措施.本文在不同温度、不同含量抗车辙剂和SBS改性剂试验条件下,采用连续密级配(AC-13、AC-16)和间断级配(SMA-13、SMA-16)两类级配进行高温车辙和低温小梁弯曲试验,对沥青混合料高温和低温性能的影响进行评价.试验结果表明:沥青混合料中添加0.4%抗车辙剂或5%SBS改性剂时,其高温和低温稳定性表现最佳.其中,0.4%抗车辙剂在改善沥青混合料高温变形能力方面优于5%SBS改性剂,而在改善低温抗裂性方面效果不及后者.间断级配沥青混合料的高温稳定性与低温抗裂性优于连续密级配沥青混合料.     

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