双掺粉煤灰-矿渣水泥砂浆动态力学性能试验研究

为了研究粉煤灰与矿渣对水泥砂浆动态力学性能的影响,用粉煤灰与矿渣替代40%的胶凝材料,其中矿渣掺量分别为0、10%、20%、30%、40%,采用?50 mm的分离式霍普金森压杆(split Hopkinson pressure bar, SHPB)试验装置,对各组砂浆进行4种加载气压的冲击压缩试验,并测试砂浆的静态抗压强度。对不同冲击气压下的应力-应变曲线、动态强度增长因子(dynamic increase factor, DIF)和破坏形态进行分析。结果表明：随着矿渣掺量的增加,砂浆的静动态抗压强度均随之增大,掺量为30%～40%时已接近甚至超过对照组砂浆,但动态抗压强度提升幅度有减缓趋势;相同矿渣掺量下,砂浆的动态峰值应力、动态峰值应变、平均应变率和极限韧性均与冲击荷载大小呈正相关,有明显的应变率效应;平均应变率在91.15～158.34 s^-1时,掺30%～40%矿渣砂浆的动态抗压强度和DIF均高于对照组;冲击气压越大,砂浆破坏程度越高,掺30%～40%矿渣砂浆的碎块数量更少、尺寸更大。因此掺30%～40%矿渣砂浆具有更优越的抗冲击性能,这为工业废料的合理利...     

再生砖粉水泥砂浆动态力学性能试验研究

为了研究再生砖粉砂浆在动压巷道中对锚杆支护结构发挥的作用,采用?50mm分离式霍普金森压杆(SHPB)试验装置,研究四种不同再生砖粉替代率(0%,10%,20%,30%)的水泥砂浆在不同平均应变率等级下的动力学特性。试验结果表明：在冲击荷载作用下,当平均应变率小于110s^-1时,掺有砖粉的水泥砂浆峰值应变均大于对照组;在30～150s^-1平均应变率范围内,砖粉替代率为10%的再生砖粉水泥砂浆动态抗压强度高于其他组;相同应变率下,砖粉替代率为10%的再生水泥砂浆极限韧性最高、吸收能量最高,因此10%替代率下的再生砖粉水泥砂浆具有良好的抗冲击性能。这对研究建筑固体废弃物的再生利用以及如何合理选择锚杆支护材料具有参考价值。     

偏高岭土对水泥土应力-应变特性影响分析

为了研究山西偏高岭土对水泥土应力-应变曲线的影响,采用无侧限抗压强度试验对不同偏高岭土掺量、不同龄期水泥土的应力-应变特征影响规律进行分析。试验结果表明:随着偏高岭土掺量的增加,水泥土峰值应力先增加后减小,当掺量为3%时,峰值应力达到最大;随着抗压强度的增加,极限应变总体呈减小趋势,变形模量呈线性增加。     

玄武岩纤维混凝土冲击韧性和微观界面试验研究

为了研究玄武岩纤维混凝土(Basalt fiber reinforced concrete,简称BFRC)在冲击荷载下的增韧性能,通过直径为74 mm的分离式霍普金森压杆(Split Hopkinson Pressure Bar,简称SHPB)试验装置得到BFRC冲击压缩全过程的动态应力-应变曲线,对纤维体积含量分别为0%、0.05%、0.1%、0.15%、0.2%、0.25%的玄武岩纤维增强混凝土进行不同应变率下的冲击试验研究,主要考察了平均应变率和纤维掺量对混凝土韧性的影响.同时利用扫描电镜(SEM)对纤维与混凝土的界面进行观察,探求纤维对混凝土的增韧机理.研究表明,BFRC的韧性存在明显的应变率强化效应,材料的峰值韧性和极限韧性与应变率呈近似的线性增长关系,应变率和纤维掺量是影响韧性的关键因素,不同强度等级的混凝土存在与其相对应的最佳纤维掺量.     

混合纤维增强水泥基复合材料的动力性能

采用变截面霍普金森杆(SHPB)对不同配比的钢/PVA纤维混合增强水泥基复合材料(HFRCC)进行了不同应变率的冲击压缩实验,并对其抗压强度、峰值应变和韧性等动力性能进行对比分析.结果表明:HFRCC材料表现出应变率敏感性;随着PVA纤维的增加,材料的变形性能更好,而钢纤维的加入则提高了其动态抗压强度;PVA纤维含量的增加能降低材料的动态强度增长因子;在低应变率下和峰值应力之前,纤维间的相对含量对HFRCC的韧性影响不大,在高应变率下,钢纤维能有效提高其韧性.     

钢纤维增强再生混凝土动态冲击力学性能试验研究

为研究钢纤维增强后的再生骨料混凝土（RAC）的动态力学性能,采用?74 mm变截面分离式霍普金森压杆（SHPB）在高应变率下进行动态冲击压缩试验,分析不同钢纤维掺量下动态抗压强度、动态增长因子（DIF）、动态冲击韧性等力学参数对动态应变速率的敏感性.结果表明：与普通再生混凝土相比,钢纤维再生混凝土动态抗压强度、动态增长因子等力学参数具有明显的应变率增强效应,并且这种增强效应随着钢纤维含量的增加而增加.钢纤维再生混凝土有10%～80%左右的动力强度增幅.不同钢纤维掺量的再生混凝土应变率敏感性有一定差异,不同应变率下材料的应变率敏感性也有所不同.     

硅酸钙板-纤维增强泡沫混凝土复合墙板的受压性能

以硅酸钙板为面板、纤维增强泡沫混凝土为芯材制备了泡沫混凝土复合墙板,研究了聚丙烯纤维掺量和泡沫混凝土容重对复合墙板受压性能的影响;并通过对受压应力应变曲线回归分析,获得了应力应变曲线方程.结果表明:随芯材中纤维掺量的增大(0~2 kg/m~3),复合墙板受压破坏时芯材的裂缝减少,抗压强度提升了76.08%,受压韧性指数提高了30.03%;随芯材容重的增大(400~600 kg/m~3),复合墙板受压破坏时逐渐从单一破坏转变为整体破坏,抗压强度大幅提高,受压韧性指数增幅较小;复合墙板受压应力应变曲线可分为弹性应变、应力硬化、应变软化和破坏4个阶段,峰值应变随纤维掺量的增加而增加,芯材容重对峰值应变的影响较小;复合墙板在受压条件下会出现界面裂缝和分层现象.     

水灰比对水泥砂浆高应变率下动态抗压力学性能影响的试验研究

为了研究水灰比对高应变率下水泥砂浆动态抗压力学性能的影响,利用分离式Hopkinsin压杆(SHPB)装置对不同水灰比(0.4、0.5和0.6)的水泥砂浆试件进行了单轴动态抗压试验研究;应变率范围为(39.4～209.4)s-1。同时进行了静态加载试验。试验结果表明,水泥砂浆的单轴抗压强度随着应变率的增大而增大,随水灰比增大,动态抗压强度值随应变率提高而增大的越缓慢;动态抗压强度提高因子DIF随应变率的增加而增大的速度随着水灰比的增加而降低。高应变率下,水泥砂浆试件的峰值压应变与极限压应变随着应变率的增大而增大,水灰比对峰值压应变值与极限压应变值的影响不大。     

花岗岩动态劈裂拉伸实验及动力作用机制

岩石作为一种常见的工程材料,其动态拉伸力学性能的准确核定及其破坏机理至关重要。借助霍普金森压杆(split Hopkinson pressure bar, SHPB)实验装置,对75块花岗岩试样进行了不同冲击速度下的动态劈裂拉伸实验,分析其动态强度与变形的应变率效应,以及冲击劈裂后的破坏形态,进而得到花岗岩试样的应变率、应力峰值、弹性模量等相关力学参数之间的关系。研究表明,在动态劈裂实验中,应变率约在100 s^-1左右,花岗岩试样开始出现裂纹;应变率在100～150 s^-1内,花岗岩试样在冲击后为破碎状态;当应变率超过150 s^-1后花岗岩在冲击加载后试样为粉碎的状态。随着应变率的逐渐增大,动态拉伸弹性模量逐渐增加,但峰值应变却随着应变率的增大而逐渐减小,表明随着应变率的提高,花岗岩的变形能力变差,更易破坏。同时提出了动态拉伸敏感性指标,该指标物理意义明确,能够准确反映岩石类准脆性介质在动态拉伸受力情况下的率效应。进而通过数值模拟,分析验证了冲击劈裂实验的应力波传播三阶段、试样破坏特性及裂纹衍生规律。进一步地,基于Hop...     

掺锂渣再生混凝土弹性模量及应力-应变曲线试验

通过改变锂渣掺量及再生粗骨料取代率,对混凝土进行轴心抗压试验。确定其弹性模量、峰值应变的计算公式;分析应力-应变曲线和应力比-泊松比曲线的变化规律;建立掺锂渣再生混凝土的本构关系。结果表明,适量再生粗骨料和锂渣可以有效提高混凝土弹性模量、峰值应力和峰值应变。再生粗骨料取代率是30%,锂渣掺量是20%时,其弹性模量和峰值应力较未掺锂渣的普通混凝土增长17.22%和48.2%。     

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