橡胶再生混凝土轴心抗拉性能试验研究

橡胶再生混凝土是一种具有较好弹性和耐撞性的利废混凝土。为确定再生混凝土中橡胶颗粒的最佳掺量,配制了5种不同掺量的再生混凝土试样,并进行了轴心抗拉强度测试,与28天抗压强度数据对比。结果得出,当再生混凝土中加入橡胶颗粒体积分数为3%时,轴心抗拉强度下降幅度最小;当加入橡胶颗粒体积分数为5%时,再生混凝土的轴心抗拉强度降低幅度最大;当橡胶颗粒的体积分数超过5%时,轴心抗拉强度不降反升;在这5种不同橡胶颗粒掺量的试件中,体积分数为3%时再生混凝土各方面性能表现最好。试验结果为橡胶再生混凝土的应用研究提供理论依据。     

废旧橡胶混凝土抗碳化性能的试验研究

以废旧橡胶混凝土抗碳化性能为研究目标,试验研究了体积分数为5%、10%、15%等三种橡胶颗粒掺量和2~4mm、30~40目、60~80目等三种橡胶颗粒粒径对混凝土抗碳化性能的影响规律.试验结果表明:橡胶颗粒的掺入对混凝土早期抗碳化性产生了不利作用,但使混凝土后期抗碳化能力有所提升;不同橡胶颗粒粒径、掺量对抗碳化性能影响不同,橡胶颗粒最佳掺量的体积分数为10%,且颗粒粒径越小效果越好.     

基于低温性能的橡胶颗粒环氧沥青混合料研究

为了分析橡胶颗粒对环氧沥青混合料低温性能的改善作用,在选择形状特征及硬度合适的橡胶颗粒的前提下,基于抗弯拉强度、最大弯拉应变、弯曲劲度模量、脆化点温度及应变能密度对不同橡胶颗粒体积掺量下的环氧沥青混合料的低温性能进行研究,并通过室内试验对不同橡胶颗粒体积掺量下的环氧沥青混合料的水稳定性及高温性能进行验证.结果表明:橡胶颗粒的细长扁平颗粒含量越小、邵尔A型硬度越大,橡胶颗粒环氧沥青混合料的压实效果及抗松散性越好;体积掺量合适的橡胶颗粒对环氧沥青混合料的抗弯拉强度、水稳定性及高温性能影响不大,但能显著提高其低温变形能力,降低其脆化点温度,改善其低温性能;在-15℃时,5%橡胶颗粒体积掺量下的环氧沥青混合料相对未掺加橡胶颗粒的环氧沥青混合料,应变能密度提高了108.0%.     

橡胶混凝土的基本力学性能

采用水、硅烷偶联剂和浓度为1%的NaOH、HCl、CaCl2溶液对橡胶颗粒表面进行改性处理,将粒度为5目、10目、40目、60目的橡胶颗粒以1∶1∶1∶2的掺配比例等体积替代20%的砂子.发现,经NaOH和CaCl2溶液处理的橡胶颗粒混凝土7d强度提高较快,而偶联剂和HCl溶液处理的橡胶颗粒混凝土7d后强度提高较快,经NaOH和CaCl2溶液处理的橡胶颗粒混凝土28d强度最高.同时,选用浓度为1%的NaOH溶液处理橡胶颗粒,分别以10%、20%、30%、40%和50%的橡胶颗粒等体积替代砂子,研究橡胶颗粒对水泥混凝土抗压强度、轴心抗压强度、弹性模量和劈裂抗拉强度的影响规律.结果表明:橡胶颗粒掺量为0~10%时混凝土强度降低较快,为10%~40%时混凝土强度降低减缓,为40%~50%时混凝土强度降低加快;橡胶混凝土弹性模量随橡胶颗粒掺量的增加呈直线下降.     

钢纤维橡胶自密实混凝土静态力学性能研究

钢纤维的桥联作用及其与橡胶颗粒的协同作用可显著改善混凝土性能,而针对钢纤维橡胶自密实混凝土的静态力学性能及其本构关系的研究较少。通过在10%、20%、30%橡胶颗粒掺量的橡胶自密实混凝土中分别外掺体积掺量为0.5%、1.0%、1.5%的钢纤维,制备出钢纤维橡胶自密实混凝土试件,进行棱柱体轴心抗压试验,探讨钢纤维掺量、橡胶颗粒掺量对试件的典型力学特征量的影响,建立钢纤维橡胶自密实混凝土轴心抗压强度的本构关系。结果表明：钢纤维橡胶自密实混凝土试件呈现延性破坏的同时,其完整性也较好;随着橡胶颗粒掺量的提高,试件轴心抗压强度逐渐降低;当钢纤维橡胶自密实混凝土中的橡胶颗粒掺量较高时(20%、30%),钢纤维对橡胶自密实混凝土轴心抗压强度无明显的增强效果;橡胶颗粒的掺入提高了试件的峰值应变,当橡胶颗粒掺量为10%时,达到最大值,增长幅度为10%;不同的钢纤维掺入量对钢纤维橡胶混凝土的峰值应变普遍有增强效果,但没有呈现出明显的规律性;轴心抗压本构关系能反映钢纤维橡胶自密实混凝土力学性能。     

轻质橡胶颗粒-砂混合土的压缩性试验研究

通过单向压缩试验,研究了橡胶颗粒-砂混合土中橡胶颗粒的压缩性以及不同橡胶掺量混合土的压缩性.为确定混合土中橡胶颗粒自身的压缩性,配制了与橡胶颗粒同级配的纯砂试样,将纯橡胶试样压缩量减去纯砂试样压缩量,得到了混合土中橡胶颗粒自身的压缩量.同时,依据混合土中橡胶颗粒和砂颗粒各自的压缩曲线,考虑混合土的压缩量等于橡胶颗粒自身压缩量与孔隙减小量之和,采用更为合理的体积分数来表达橡胶颗粒的掺量,建立了一种混合土的压缩模型,并与试验结果进行了对比验证.结合模型和试验结果发现,橡胶颗粒掺量的界限质量分数为20%,工程应用中不应超过此临界值.     

环氧沥青混凝土增柔增韧改性技术

为了解决环氧沥青混凝土在钢桥面铺装层使用中存在的固化后脆硬,同桥面板变形一致性差,以及易出现开裂的问题,通过在环氧沥青混凝土中添加橡胶颗粒、聚酯纤维来提高其柔性和韧性。采用低温弯曲试验和弯曲疲劳试验,评价不同掺量的橡胶颗粒和聚酯纤维对环氧沥青混凝土弯曲破坏应变和疲劳寿命等指标的影响。研究结果表明:橡胶颗粒和聚酯纤维能改善环氧沥青混凝土的柔性和韧性,橡胶颗粒在与环氧沥青形成的共混体系中通过银纹作用显著提高了混合料的柔性性能,其最佳掺量为2.1%;而掺入聚酯纤维后,环氧沥青混凝土中形成的结构沥青和纤维网共同作用,大大提高了混合料的韧性性能,其最佳掺量为0.3%。     

橡胶颗粒沥青混合料低温性能影响因素研究

通过对橡胶颗粒沥青混合料进行低温弯曲试验,并运用统计学检验和灰熵法对试验结果进行分析。结果表明:对于不同掺量橡胶颗粒的沥青混合料,掺加3%橡胶颗粒能显著提高沥青混合料的低温性能,其灰熵关联度顺序为:沥青用量>流值>毛体积密度>空隙率。     

废旧轮胎橡胶颗粒对水泥浆和砂浆抗裂性能的影响

通过圆环开裂试验和弯曲试验探讨了不同体积分数的废旧轮胎橡胶颗粒掺入水泥浆和砂浆后对抗裂和变形性能的影响．研究结果表明，在水泥净浆中掺入废旧轮胎橡胶颗粒，可延迟圆环试件的开裂时间，提高抗裂性，延迟时间的长短与橡胶颗粒的掺量有关，当橡胶颗粒的体积分数在20％～50％时，延迟效果最为显著；在砂浆试件中掺入橡胶颗粒，可显著改善其弯曲变形性能，试件破坏形式为延性破坏，破坏时的极限变形值比基准试件大得多，并且随着橡胶颗粒体积分数的增加而迅速增大．     

干湿循环对橡胶颗粒稳定轻质土的单轴抗压特性研究

通过无侧限抗压强度试验,研究了干湿循环条件下橡胶颗粒稳定轻质土在单轴压力作用下的变形特性及和强度特性,得到了应力-应变曲线与干湿循环次数、橡胶颗粒掺量的关系。无侧限抗压强度试验结果表明：橡胶颗粒稳定轻质土的应力-应变曲线为软化型,可以被概括为压密、弹性变形、应变软化3个特征阶段。橡胶颗粒稳定轻质土的弹性模量、无侧限抗压强度均随着循环次数的增多逐渐降低,在橡胶颗粒含量大于30%后,受干湿循环影响逐渐减小。基于试验数据建立了橡胶颗粒稳定轻质土的强度预测模型,可以对不同掺量橡胶颗粒稳定轻质土在干湿循环作用下的无侧限抗压强度进行准确预测。     

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     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has