膜结构路面器材通过性机理分析

为了研究新型膜结构路面器材,保障轮式车辆在松软路面上的通过性,运用车辆地面力学理论对路面器材的沉陷特性进行分析,探讨了膜内张力对最大沉降量的影响。将理论分析结果和仿真结果进行对比,验证了沉降计算公式的合理性。选取车辆挂钩牵引力作为评判车辆软土通过性的准则,将受力分析法和能量法相结合建立轮胎行驶的挂钩牵引力计算公式,定性得到附着系数μ和最大沉降量z0对车辆通过性的影响关系。结果表明,在所选条件下,膜内张力对最大沉降量影响不大,通载试验初步验证了通过性理论的合理性。     

用相似理论研究重型矿用自卸车驱动轮的牵引力

本文研究重型自卸汽车在砂地上行驶时的越野通过性,分析了影响挂钩牵引力的诸因素,采用量纲分析法,建立了兀关系式。通过模拟试验,得出了驱动轮在砂地上行驶时的挂钩牵引力预测公式。     

基于DCT轻型越野车的牵引力特性仿真

提出双离合器式自动变速器(DCT)轻型越野车依靠调节发动机、轴间差速器和制动器的联合牵引力控制策略,分析了DCT传动的工作原理,建立了换挡过程的动力学数学模型.在Matlab/Simulink仿真软件平台的基础上,建立了DCT和机械式自动变速器(AMT)轻型越野车驱动动力学仿真模型,并利用仿真模型对车辆在低坡度分离路面和对接路面上的起步加速过程进行仿真.仿真结果表明,所提出的牵引力控制策略能够提高车辆在低附着系数路面上的牵引力,DCT车辆的牵引性能明显优于AMT车辆的牵引性能.     

基于滑模观测器的电动汽车最大牵引力估计

为实现双电机四轮驱动电动车在不同路面的最大驱动力, 提出了基于LuGre摩擦动力学模型和滑模观测器(SMO： Sliding Mode Observer)的牵引力控制策略。利用LuGre动力学模型中反应路面条件的参数θ, 实现路面条件在线辨识。通过SMO对电动汽车在纵向行车工况下、 轮胎小滑移率时, 主动估计路面条件参数θ, 进而估算其最佳滑移率, 获得路面可提供的最大牵引力。同时采用动态饱和非线性控制策略限制电机的最大输出力矩, 保证电动车在不同路面条件下防滑行驶。仿真实验表明, 基于滑模观测器的最佳滑移率估计方法可在不同路面条件下提供电动汽车最大牵引力, 对汽车行驶的主动安全性有重要意义。     

越野车充气轮胎小卵石路面行驶性能仿真分析研究

基于3维DEM-FEM耦合仿真分析方法,研究越野车充气轮胎小卵石路面的行驶性能.在建立某越野车轮胎的3维有限元模型和小卵石路面离散元模型的基础上,利用本研究室开发的专用分析软件ORV-SAND仿真分析越野轮胎在卵石路面的行驶行为,得到了不同滑转率（10%、20%、30%）下不同胎面结构轮胎的法向反作用力、轮辋下陷量、总牵引力、挂钩牵引力以及行驶阻力,并与相关实验进行了比较.     

用小波变换分析路面不平度及振动响应

运用小波变换方法，对车辆的振动响应与路面不平度的关系进行分析．根据路面样本值，运用ARMA模型建立路面不平度时间序列，建立1／2车辆平顺性模型．将路面不平度时间序列作为输入，分析汽车的振动响应．结果表明，将小波变换引入路面激励和汽车振动响应的分析中，可以清楚地了解信号的时频特性，识别车辆振动响应与路面不平度的关系，从而可以通过路面特性分析车辆平顺性能或由振动响应推断路面激励。     

履带机械地面力学建模及牵引性能仿真与试验

针对现有履带机构仿真模块难以适用于无支重轮式矿用履带车辆的局限性,通过分析履带-地面交互力学机理,以每块履带板与地面的力学作用为基元,根据Bekker理论建立了履带沉陷、地面垂直力、牵引力、侧向力、行驶阻力的数学模型,并基于此模型和FORTRAN语言开发了履带一地面交互力学用户子程序.将该模型结合多体动力学仿真软件ADAMS的二次开发技术,建立了某型矿用履带车辆虚拟样机模型,并进行了牵引性能动力学仿真分析.研究表明,该仿真模型能够对行驶阻力和挂钩牵引力进行分析预测,误差小于15%,在允许范围之内,可以作为履带机构牵引设计的工具,且具有更好的普适性.     

汽车TCS控制逻辑的仿真研究

汽车牵引力控制系统是一种新型的主动安全控制技术。本文从实用角度出发，建立车辆动力学模型，提出了应用于车辆在低附着路面及左右分离路面起车的控制逻辑，并在本文所建立的车辆动力学模型上进行了仿真研究。仿真的结果表明本文所提出的控制方法切实有效。     

汽车弹性元件对平顺性的影响分析及试验优化

基于Matlab/Simulink应用环境,建立1/4车辆三自由度平顺性模型,对随机路面输入下的汽车平顺性进行仿真。应用参数敏感度理论,分析悬架弹簧刚度、悬架橡胶件垂向刚度、座椅刚度和轮胎刚度对座椅和地板垂向加速度均方根值的影响。根据仿真分析结果,对某款轿车橡胶元件进行了试验优化。仿真和试验结果表明:改变橡胶元件刚度可以有效地提高汽车平顺性。     

麦弗逊悬架参数变化对整车平顺性影响分析

设计了某车型前麦弗逊式悬架,通过搭建麦弗悬架动力学模型并对其进行动力学仿真及平顺性仿真分析,得到车辆以不同车速通过随机路面的振动分析数据,以此评价车辆行驶平顺性.通过逐步改变悬架刚度和阻尼值分析对车辆行驶平顺性的影响,进而得到提高车辆行驶平顺性的方法.     

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