减振器示功图面积对车辆平顺性的影响

为了研究减振器示功特性与车辆平顺性之间的影响机理,基于流体力学原理建立了液压双筒式减振器数学模型,并对其进行了台架试验.在此基础上,根据减振器外特性仿真曲线,提出了示功图总面积量化指标.结合车辆系统振动原理,建立了示功图总面积与簧上质量垂向振动加速度、悬架动行程以及轮胎动载荷之间的数学关系.基于整车振动模型,定量分析了示功图总面积对簧上质量垂向振动加速度、悬架动行程以及轮胎动载荷的影响规律.结果表明:当示功图总面积较小时,车辆平顺性和行驶安全性均出现明显恶化现象,但示功图总面积过大也会引起振动加速度和轮胎动载荷的增大,同时还会影响二者振动能量在频域内的分布.     

车用双筒液压减振器动态响应的试验与仿真

在ADAMS环境下，开发出双筒液压减振器的虚拟样机，并研究了减振器强非线性。将减振器速度外特性试验曲线拟合为速度外特性不对称非线性迟滞环，取代了常规减振器建模中的速度外特性不对称双线性化模型。采用实际减振器的几何参数、物理特性以及动态约束，经动态仿真分析表明，数值仿真与台架试验结果基本相符。因此，该减振器虚拟样机建模是正确的，可以减振器优化设计和整车性能匹配改进提供开发平台。     

车辆减振器技术刍议

本文简单介绍了几种新型减振器技术研究成果,包括电流变液体减振器、节流式磁流体阻尼可调减振器、双筒液压充气减振器、磁性减振器、半主动悬挂减振器等7种减振器的构成及特点。为我国进行车辆减振技术提供参考。     

可变阻尼减振器外特性仿真与试验

分析了所开发的可变阻尼减振器的工作原理和阀系特性。根据流体力学缝隙流动、管嘴流动及并联管路流量计算理论,推导出阻尼力计算公式,用MATLAB建立了可变阻尼减振器的数学模型,通过仿真得到了示功图和速度特性,并按照减振器台架试验标准QC/T545进行了试验,得到了外特性试验数据。将仿真结果和试验数据进行比较,证明应用并联管路流量计算理论建立的数学模型正确可靠,符合实际要求,准确地描述了阻尼力随行程变化的特性,可用于可变阻尼减振器的设计和性能预测。     

数论函数中的R—空间的性质（Ⅱ）

本文证明了如果Ｔ是一个Ｒ－空间，ｆ是一个积性函数，ｆＴ，ｆ（ｎ＋Ｂ）－ｃｆ（ｎ）∈Ｔ［ｎ］，其中Ｂ为正整数，ｃ为复常数，那么必有ｃ＝±１，而且对于任何素数ｐ皆有非负整数αｐ使ｆ（ｐαｐ＋ｒ）（ｆ（ｐαｐ））ｒ－１＝（ｆ（ｐαｐ＋１））ｒ，ｒ＝２，３，…．进一步，如果ｃ＝１或ｐ≠２，则有ｐαｐ｜Ｂ，而当ｃ＝－１时２α２｜２Ｂ，推广了以前的结果     

轨道车辆液压减振器低频阻尼特性试验研究

在轨道车辆液压减振器开发过程中,通常会存在由于减振器泄漏等原因,导致其在低频阶段阻尼力值过低而无法满足技术要求的情况。为了研究减振器在低频阶段泄漏产生的原因及其对阻尼力值的影响力程度,通过改变导向套与活塞杆间隙、活塞表面与阀片贴合度及支撑环形式等的试验对比,研究其对减振器泄漏程度所造成的低频阶段阻尼力值的变化。试验结果表明,导向套与活塞杆间隙、活塞表面与阀片贴合度对减振器低频阻尼特性有较大的影响,而受活塞支撑环的影响相对较小,导向套与活塞杆间隙主要作用于液压减振器的复原行程内。     

一类奇异和非奇异边值问题正解存在性

讨论了两点边值问题（Ψｐ（ｙｒ＋ｆ（ｘ，ｙ）＝０，ｙ（０）＝０，ｙ（１）＝ｈ〉０；和（Ψｐ（ｙｒ＋ｆ（ｘ，ｙ）＝０，ｙ（０），ｙ（１）＋ｋｙ（１）＝Ｈ，Ｋ〉０正解的存在性和唯一性。     

论Opial—Beesack不等式

设ｆ（ｘ）∈ＡＣ［０，Ｈ］，产Ｆ（０）＝ｆ（ｈ）＝０，则有∫＾ｈ０｜ｆｆ＇｜ｄｘ≤１／２（ｈ／２）＾２／Ｑ（∫＾ｈ０｜ｆ＇｜＾ｐｄｘ）＾２／ｐ－２／ｑ｛｜ｆ＇｜＾ｐｄｘ）＾２－１／４（∫＾ｈ０｜ｆ；｜＾ｐｃｏｓ（２πｘ／ｈ）ｄｘ）＾２｝＾４／ｑ其中１＜ｐ≤２，Ｑ＝Ｐ／（Ｐ－１）．（２）显著比（１）优秀，实际上我国已证得更一般的结果。     

L(p)(p>1)‖f‖_p与E_f(p)中的连续性

证明 了 Ｌ （ｐ）（ｐ＞ １）中‖ ｆ‖ 与 Ｅ （ｐ）关 于 ｐ 的 连续 性 ，即 ：当 ｐ０＞ ｐ＞１，ｆ（ｘ）∈ ｐ ｆＬＰ （Ｅ ）时 ，ｌｉｍ ‖ ｆ‖_ｐ ＝‖ ｆ‖_Ｐ ，ｌｉｍ Ｅ （ｐ）＝Ｅ （ｐ０）。 ０ ０ ｆ ｆ ｐ→ｐ０ ｐ→ｐ０     

抗蛇行减振器常见故障对高速列车动力学性能的影响

以CRH380B型动车组为实例,结合实际中常见的抗蛇行减振器故障,基于车辆动力学理论,利用动力学仿真软件SIMPACK建立动力学模型,通过改变抗蛇行减振器阻尼特性来模拟不同故障类型,从而对车辆进行动力学研究.结果表明:当抗蛇行减振器故障后的剩余阻尼力在标准阻尼力50%以下时,对车体平稳性、稳定性、曲线通过性能均有很大影响.其中当抗蛇行减振器剩余阻尼力为标准力值的50%时,车体垂向和横向平稳性指标分别达到了1.85和2.20,脱轨系数达到了0.45,非线性临界速度降低到了271km/h.得出抗蛇行减振器的最佳阻尼特性:当卸荷速度为0.03m/s,卸荷力为8~9kN时,车辆各动力学性能达到相对最优状态.     

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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