矩形截面恒力特性直流电磁铁的设计分析

提出了一种新的矩形截面直流电磁铁结构,得出恒定的力-位移特性。在磁路分析的基础上,导出了产生恒力特性的条件,并且还讨论了电磁铁尺寸对力特性的影响。通过一个算例的ANSOFT有限元软件计算结果表明：笔者提出的电磁铁结构和得出的结论是有效的。笔者的方法和结论可用于该类恒力电磁铁的研发和设计。     

直流偏磁下变压器绕组及垫块振动特性分析

直流偏磁使得变压器绕组振动加剧,目前采用将绕组简化为忽略垫块结构的圆柱模型的建模方法误差较大.建立包含垫块的线饼式绕组精细化模型,通过电磁场-结构场-流体场多物理场耦合的方法,在对直流偏磁下变压器磁场分布进行分析的基础上,对绕组及垫块的振动位移特性进行研究且进行实验验证.结果表明:直流偏磁下变压器漏磁增加且在特定角度分...     

新型含磁准零刚度隔振器建模分析

旨在建立一类新型含磁准零刚度隔振器系统的力学模型。该系统通过并联具有负刚度特性的磁力弹簧和线性正刚度弹簧,使系统在小位移内具有刚度渐硬特性,较大位移内同时具有刚度渐硬和刚度渐软特性,并推导出其动力学方程。通过分析力-位移结构特性、刚度-位移结构特性,获得其实现准零刚度的条件。研究结果为实际工程应用中隔振器的设计及参数优化提供了理论参考,具有一定的实际意义。     

线性压缩机用动磁式直线电动机

研制了一种新型直线压缩机驱动用动磁式直线振动电动机.建立了电动机磁路物理模型,并对磁路数学模型、电动机动子动力学模型和驱动电路模型进行了求解,得到了驱动电压与动子位移关联式,分析了电动机参数对动子运动特性和电动机性能的影响.运用电磁场有限元方法对动磁式直线电动机电磁场模型求解,磁通分布揭示了电磁力产生机理;运用直线电动机样机静态特性实验数据验证了数值分析的有效性.数据分析揭示了动磁式直线电动机力-位移-电流之间的关系,为压缩机和电动机控制系统设计奠定了基础.     

液压阀用本质安全型防爆电磁铁吸力特性研究

摘要：设计了一种电阻为220 Ω,额定行程为2.3 mm的液压阀用本质安全型防爆电磁铁,通过经验公式初步设计出电磁铁的结构尺寸,利用Ansoft仿真软件对设计出的电磁铁结构进行仿真,得出电磁铁的静态特性仿真曲线,开发了电磁铁试验样机,测试说明实验数据与仿真结果吻合,表明设计出的本质安全型防爆电磁铁达到了设计要求.     

变压器铁心电磁振动仿真及影响因素研究

为了研究变压器铁心的电磁振动的多场耦合问题,使用应变能原理修正铁心磁-结构耦合关系对变压器铁心的本体振动进行仿真研究.将硅钢片磁化特性曲线导入到仿真模型中,计算得到线圈中的电流密度以及铁心闭合回路中的磁感应强度分布,实现电场与磁场的耦合.利用应变能原理对磁致伸缩力进行等效,并以等效磁致伸缩力为耦合变量对铁心进行结构瞬态...     

新型多维隔减震装置在高烈度区工程中的应用

为提升建筑结构多方向的抗震能力,基于黏弹性材料的高耗能特性提出了一种由筒式阻尼器和隔震支座组成的新型多维隔减震装置,并应用于云南某小学的实际工程.首先通过试验得到筒式阻尼器的耗能特性,然后建立多维隔减震装置的力学模型和受控结构运动微分方程,通过对比计算研究装置的多方向隔减震效果.结果表明:装置中的筒式阻尼器具备较强的耗能能力,且其力学性能会随激励频率和幅值变化而变化;结构中加入新型装置后,水平和竖向的地震响应均得到有效控制;在EI Centro地震波作用下,与橡胶隔震结构相比,多维隔减震结构X方向和Y方向的最大隔震层位移分别降低39.5%和38.9%,X方向和Y方向结构最大层间位移分别降低39.4%和45.5%,Z方向最大位移和加速度响应分别降低12.2%和6.3%,说明新型多维隔减震装置可有效减轻结构多方向地震响应.     

组合式永磁同步直线电机端部效应力研究

为了改善永磁同步直线电机的推力波动特性,针对其结构特点,提出了组合式永磁同步直线电机这一新型结构并介绍了组合式永磁同步直线电机的结构特点;以平板式短初级长次级永磁同步直线电机为例,用傅立叶级数方法对传统永磁同步直线电机和组合式永磁同步直线电机的端部效应力进行了分析,获取了最小化端部效应力的铁芯长度选取方法;利用有限元方法对两种电机的端部效应力解析结果进行仿真验证,用两种电机的原型样机实验平台进行了静磁阻力实验.仿真和实验结果表明,组合式永磁同步直线电机有效减小了端部效应力和静磁阻力,使电机的推力波动特性得到明显的改善.     

电磁铁数学建模及仿真

为了更深入了解阀用电磁铁的磁链、电感随其他电磁参数的变化规律,通过数学模型和Ansoft仿真分析,研究了电磁铁的电磁特性曲线,为进一步对阀用电磁铁进行控制提供了理论基础。     

静电悬浮加速度计地面试验系统微位移驱动器控制模型研究

介绍了超磁致伸缩驱动器（GMA）的结构,从有助于理解压磁效应的角度,建立了GMA的静态位移力模型和磁-机耦合模型,并对后者进行了仿真研究。仿真结果显示机械部分响应时间比较缓慢,减小阻尼会带来一些不利影响,如超调量增大。波动增大,要改善系统的动态性能,需要在控制系统部分增加合理的调节器。     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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