内插新型转子圆管的管内流阻和转子旋转特性

在已有螺旋转子结构的基础上,提出一种改进型转子结构,以便减小内插转子引起的阻力增加。对内插不同结构参数新型转子的管内流动阻力及转子旋转特性的实验结果表明:流速较低时新型转子即可旋转,转子转速与来流速度近似呈线性关系;转子叶片螺旋角对流动阻力及转速影响较大,正反旋向转子相间放置既可解决转子同向布置时沿流体流动方向转子转速逐渐减小的问题,又可使流阻进一步降低。通过合理选择转子结构参数,可使流动阻力比光管的仅增加2.5倍左右,远低于内插原有转子时的阻力增加。     

设备故障诊断技术的实用方法总结

转子质量偏心的振动特征、转子质量偏心振动随敏感参数的变化、转子质量偏心的故障原因、转子部件缺损的振动特征、转子弓形弯曲的振动特征、转子不对中的振动特征。     

转子通风结构对永磁电机转子流体场和温度场的影响

为降低实心转子永磁电机转子温升,以一台全空冷315kW、6kV实心转子永磁电机为例,建立了该电机转子无通风沟的三维全域流体与固体耦合传热数学模型,给出了计算区域边界与假设条件,采用有限体积法求解三维流体与固体耦合传热数学方程组,得到了转子体的温度分布,与实验数据对比验证了计算方法的准确性.由于转子无通风结构,转子体的温度较高.为了降低转子温度,提出了在电机转子上开轴径向通风沟的多种结构方案,研究了转子径向通风沟数量与位置对转子内温度分布及空气运动的影响.结果表明:在转子上开轴径向通风沟能够有效降低转子温度,为实心转子永磁电机通风系统设计提供了理论依据.     

小转子未固定的PFNA治疗Evans-Jensen Ⅲ型转子间骨折的有限元分析

建立小转子未固定的Evans-JensenⅢ型转子间骨折的PFNA内固定有限元模型,分析股骨转子区域在负重后及模拟髋内翻发生过程的应力变化。建立小转子不固定及固定的Evans-JensenⅢ型转子间骨折PFNA内固定的三维有限元模型,分析股骨转子间骨折块的生物力学应力环境。无论小转子是否固定,Evans-JensenⅢ型转子间骨折使用PFNA内固定后Von Mises应力分布均匀,股骨转子间骨折块稳定性良好,但固定小转子后的PFNA内固定其应力分布的最大Von Mises应力值更大。PFNA内固定能有效维持小转子未固定的Evans-JensenⅢ型转子间骨折的稳定性,有限元分析结果能够为临床实践提供术前依据。     

Jeffcott转子-环流耦合系统动力学建模及分析

基于湍流整体流动理论和摄动分析,建立了Jeffcott转子-环流耦合系统的动力学模型,并以大型屏蔽电机泵转子系统为例,采用复模态分析方法分析了转速、转子偏心和定、转子壁面摩擦效应对转子-环流耦合系统动力学特性的影响.结果表明：环流将导致转子的固有频率大幅下降,并产生模态分叉和跳变;转子偏心将导致转子失稳并使其失稳转速下降;定、转子壁面的摩擦效应能够显著提高转子的失稳转速.
     

引信球转子动力学特性模拟试验

为了验证引信球转子理论分析的正确性,采用由激光打标机对旋转状态下转正运动过程中的引信球转子表面打标痕的方法设计了一种研究球转子运动的试验,测定了5种力学参数球转子的运动轨迹.试验和理论分析结果均表明球转子相对于其腔室的运动轨迹为空间螺旋线,球转子的解除保险运动受初始进动角、转动惯量差异及质心位置影响很大.通过减小球转子与其腔室之间的滑动摩擦将增长球转子的运动轨迹并减小动态平衡角,而加大球转子质心偏心会增大球转子的动态平衡角.     

透平机械转子系统不对中故障定量诊断监测方法研究

针对透平机械转子系统不对中故障程度难以定量诊断的问题,提出一种基于转子的状态监测数据建立转子平行不对中量与节点振动通频幅值的关系曲线来定量诊断转子平行不对中故障的方法。对平行不对中状态下的转子进行受力分析得到转子不对中激励力,通过建立的转子试验台有限元数值分析模型计算得到不同不对中激励力下的转子节点振动通频幅值,进而通过分析转子节点振动通频幅值与不对中量的对应关系曲线及转子运行正常数据对关系曲线进行修正;根据监测得到的转子节点振动通频幅值反推出转子平行不对中量,达到对平行不对中故障定量诊断的目的。最后试验验证了定量诊断方法的可行性。     

遗传算法在碳纤维复合材料高速转子优化设计中的应用

对多层结构碳纤维复合材料转子进行了高转速下的静力学分析 ,建立了多层嵌套结构碳纤维复合材料转子的强度与转子的材料密度、转速、纤维铺设角、各层径向壁厚以及各层间过盈配合量间的数学关系式。应用遗传算法进行了转子结构的优化设计 ,解决了多层结构碳纤维复合材料高速转子设计中如何寻求转子最优外形和工艺参数的难题。通过对转子各层的纤维铺设角、各层径向壁厚以及各层间过盈配合量进行优化 ,获得了转子的最佳几何外形和工艺参数 ,使转子的储能密度较优化设计前提高了 1 36 % ,最大限度地提高了转子的储能能力。此优化设计方法为多层嵌套结构碳纤维复合材料转子的储能密度优化设计提供了有效手段     

某涡扇发动机转子系统稳定裕度及其灵敏度分析

某型涡扇发动机转子系统由3个单转子系统构成。将该三转子系统在耦合处分开,把耦合力作为单个转子上的外力,并利用集总参数法和各节点的振动微分方程表达式建立单个转子的振动方程。利用各转子间耦合部件的总体耦合矩阵将单个转子的振动方程耦合在一起,建立了整个三转子系统的振动微分方程。通过求解整个系统的振动微分方程,得到整个系统所有模态的对数衰减率,并进一步求出系统的稳定裕度和其灵敏度。研究结论表明:提高高压转子轴承的阻尼和高压转子的弯曲刚度可以有效提高系统的稳定裕度;联轴器的存在和转子转速的提高都会降低转子系统的稳定裕度。     

1 000 kN电机转子压铸机的研究及应用

针对传统的电机转子压铸设备水平低、电机转子铸铝质量不稳定等问题，研制和开发了1000kN电机转子压铸机，用于Y80～Y160电机转子投影面积内的各种电机转子的压铸．该压铸机完成了转子压铸生产工艺的全过程，实现了全流程机械自动化生产。     

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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