泥石流冲击荷载下圆钢管的破坏机理分析

为研究泥石流冲击荷载下圆钢管构件的破坏机理,利用LS-DYNA对一端固定的圆钢管构件进行数值模拟分析.通过改变钢管的直径、壁厚、撞击点高度,以及冲击物的质量、冲击物的速度等变量,计算了243个工况,并对圆钢管构件的动力响应进行对比分析.结果表明,钢管构件的壁厚、直径越大,则构件的冲击力越大,冲击点处的变形区域越小,产生的位移越小;在不同的撞击高度下,撞击自由端处引起的位移是柱脚位移的2倍,而冲击力相差不大;冲击物的速度、质量越大,则冲击能量越大,冲击力越大,构件局部发生的变形区域更大,整体产生的位移也随之增大.     

超高压超临界撞击流方法制备破壁灵芝孢子粉的机理分析

从灵芝孢子粉破壁的过程出发,结合灵芝孢子粉的结构,分析了采用超高压超临界撞击流方法制备破壁灵芝孢子粉的机理。分析结果表明：高速射流引起的撞击是造成灵芝孢子破壁的最主要原因。     

原位纳米测试技术研究灵芝孢子孢壁弹性模量和硬度

采用原位纳米测试技术研究灵芝孢子孢壁的力学性能。进行了试样制备方法的探索,利用原位纳米力学测试与分析系统,分别测试未破壁和机械法破壁的灵芝孢子孢壁的弹性模量和硬度。结果显示:未破壁灵芝孢子的平均弹性模量为2.0 GPa,硬度为0.13 GPa;机械法破壁灵芝孢子的平均弹性模量为4.36 GPa,硬度为0.26 GPa。研究结果为分析孢子的破壁机理提供了必要的参数。     

基于血液撞击损伤机理的高速螺旋血泵仿真分析

采用血液流变学及应力波理论,对高速螺旋血泵中血液撞击损伤机理进行研究,分析红细胞-固壁撞击破碎的过程和红细胞膜冲击破碎的条件;通过血液撞击损伤实验,对不同撞击速度下血液生理性能指标变化及红细胞微观形态进行观测分析,得出红细胞破碎的临界撞击速度;结合所设计的螺旋轴流血泵及螺旋混流血泵,应用多相悬浮体CFD 仿真技术,对血泵中的速度场进行仿真分析.研究结果表明当垂直撞击速度达到6 m/s 以上时,红细胞有可能发生破裂而导致溶血;所设计的螺旋混流血泵中血液由于红细胞撞击破碎而导致的溶血情况并不严重,其血液撞击损伤程度比螺旋轴流血泵的撞击损伤程度低.     

泥石流块石冲击下钢框架动力响应分析

探究在泥石流块石冲击下山地地区钢框架结构建筑物的动力响应,运用显示动力学方法对5层钢框架结构计算模型进行数值模拟,分析不同速度的冲击物作用在结构不同位置时的动力响应.结果表明:在冲击物速度不变的情况下,冲击荷载作用于结构的不同位置时,其动力响应差别较大,节点处的响应明显小于梁、柱部位,边跨节点响应要大于中间跨节点;冲击物作用于节点时结构中边跨节点的材料最先进入塑性,且最容易发生破坏,而中间跨节点处相连接的3根梁受到的等效应力最大,材料最先进入塑性;通过对比沿冲击方向梁上某些单元的等效应力,可知在冲击物作用下节点处所承受的能量比梁的要大,撞击所引起的动力反应是局部性的;柱子在冲击过程中吸收的能量最多,是结构受到冲击时最容易发生破坏的部位.     

高速磁悬浮车辆复合板抗冰雹冲击动力响应研究

为解决高速磁悬浮的抗冲击问题,建立了磁悬浮列车车身夹芯复合板的有限元模型和冰雹的SPH粒子模型,利用大型动力有限元分析软件LS-DYNA,模拟了列车高速行进过程中车身复合板遭受冰雹冲击的动力响应及损伤破坏问题.通过分析研究,给出了不同冲击速度下的复合结构的应力、应变计算结果,同时给出了冲击破坏模式.结果表明采用SPH方法模拟冰雹冲击行为具有合理性和准确性.      

灵芝孢子的破壁方法及其药理作用研究进展

灵芝,其子实体、孢子粉均可食用或入药,其中灵芝孢子具有灵芝的全部遗传活性物质,其药用价值日益受到重视.研究发现,灵芝孢子具有抗癌、免疫调节、抗氧化、神经保护、保肝和抗糖尿病等药理作用,但由于灵芝孢子壁具有一层坚硬的几丁质外壳,不易破碎,影响其功效的发挥.为了灵芝孢子的合理开发和应用,综述了近年来灵芝孢子的破壁方法及其药理作用,以期为灵芝孢子产品的研究与开发提供一定的参考价值.     

落石撞击双柱式桥墩破坏模式及抗撞性能分析

基于非线性接触有限元数值模拟技术建立高精度落石-桥梁碰撞模型,对不同参数下桥墩的动态响应和破坏模式进行参数分析,主要研究的参数包括:桥墩上部质量、桥墩箍筋间距、落石质量与速度以及撞击位置.分析了我国规范给出的建议桥墩抗撞能力计算方法,并与实际抗撞能力对比.研究发现:落石高速撞击下桥墩的破坏形式以弯曲破坏为主,但是上部结构质量和落石速度的增加和撞击位置的改变会使桥墩的破坏形式由弯曲破坏向剪切破坏转变.落石冲击桥墩上部造成的破坏程度相比其他位置小,改变撞击方向会显著影响撞击点上方的桥墩侧向位移.我国公路桥梁抗震设计细则公式给出的计算方法低估了桥墩实际的抗撞能力,轴压力对桥墩的抗撞性能有明显提升,建议考虑在计算公式加入轴压力因素.     

意外撞击和冲击波作用下气瓶的动态响应分析

基于任意拉格朗日多物质流-固耦合算法,对空气采用ALE网格,对炸药采用JWL状态方程,分析了爆炸冲击波单独作用和高速子弹与冲击波联合作用下高压气瓶的动态响应.结果表明,在冲击波作用下气瓶应力急剧上升,气瓶出现屈服并发生屈曲,爆心距瓶体越近,气瓶受冲击波的影响越大;联合作用时应力相互叠加使得气瓶应力值比单独作用时有明显增大,变形相对于高速撞击和爆炸波单独作用显著增加,塑性变形区域变大,破坏程度更加明显.     

多孔材料冲击波效应的数值模拟

采用有限元方法模拟了开孔泡沫铝在冲击载荷下的响应,研究了冲击响应与相对密度和冲击速度的关系。研究结果表明:开孔泡沫铝受到较大速度冲击时,先驱产生的弹性波使试样达到准平衡状态。当试样受冲击端的应力超过平台区应力达到密实化区的应力时,冲击波产生。冲击波的形成将使试样两端的应力在一定的时间内不平衡,产生冲击波效应。具有相同的相对密度时,冲击速度越大,冲击波效应越明显,冲击波速度也越大;在相同的冲击速度下,相对密度越大冲击波效应越不明显。     

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     

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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