空气轴承的弹性均压槽力学性能分析与测试

该文设计了一种新型空气轴承.建立了弹性环形薄板的有限差分数值计算模型.设计了含有均压槽气体润滑轴承的计算模型和弹性环形薄板的有限差分数值计算模型的耦合计算过程.探索了用多重网格法求解四阶偏微分方程(弹性薄板变形控制方程)的迭代过程,取得成功.对新型气体静压推力轴承的环形弹性均压槽弹性变形的检测结果表明:均压槽的宽度、深度都能随设计压力的改变产生满足控制要求的尺度变化,表明这种结构的设计、制造和检测都是成功的.     

用可变截面均压槽实现高刚度空气静压轴承的结构设计

提出了弹性可变截面均压槽的概念,并以此概念为核心提出了用弹性环形薄板实现可变截面均压槽、可变节流器复合作用的推力轴承结构和用弹性环形薄板实现可变截面均压槽与刚性均压槽相组合作用的推力轴承结构.对新型气体静压推力轴承的环形弹性均压槽弹性变形的检测结果表明:均压槽的宽度、深度都能随设计压力的改变产生满足控制要求的尺度变化,说明这种结构的设计、制造和检测都是成功的;对新型气体静压推力轴承的载荷特性的检测结果表明:在检测范围内轴承的刚度处处都比较高,约为150 N/μm.有可能用于载荷变化较大的场合,有较好使用前景.     

考虑紊流和滑移影响的液态金属润滑螺旋槽轴承设计

为了研究液态金属作为润滑介质时对螺旋槽轴承性能的影响,针对液态金属黏度低与接触角大等特点,建立了考虑紊流和边界滑移影响的轴承性能计算模型,进行了液态金属润滑螺旋槽轴承设计。基于螺旋槽轴承的特殊结构,在非正交坐标下运用有限差分法以及局部积分法求解了雷诺方程,得到轴承膜厚压力分布;采用Ng-Pan紊流模型并综合滑移长度模型(SLM)和极限剪应力模型(LSSM),分析对比了考虑紊流滑移影响和层流无滑移时的轴承性能;研究了槽数、螺旋夹角等结构参数对轴承静动态性能的影响,确定了轴承各结构参数的最佳取值。结果表明:适当的半滑移设计可以有效提高轴承承载能力并减少空化区域面积;在槽数为8～12、螺旋夹角为60°左右、槽深为20μm、沟脊比为1时,轴承可以获得良好的静动态性能。研究工作对国产高性能CT设备的液态金属轴承设计具有一定的指导意义。     

超薄圆盘等分孔和槽加工工艺

本文针对外柱面上均匀分布多孔和槽的圆盘件,设计并制造了专用工装夹并对其主要工序进行分析,指出了加工超薄圆盘件时应注意的问题和处理方法。     

相似原理在冷态模拟粒化钢渣中的应用

在实验室用石蜡冷态模拟液态钢渣进行气淬粒化试验,讨论了气体压强、气流速度、气体流量及液态钢渣渣流落下距离对粒化效果的影响.结果表明,粒化后石蜡的粒度分布与气体的压强、流量和气流速度成反比.应用相似原理和量纲分析得到相应的准数,通过气淬石蜡的结果和计算得出,当气体的压强p=0.56MPa,气流速度v=93.33 m/s,液态钢渣流的落下距离l=18.7 cm,气体的流量Q=338 m3/h时被粒化的液态钢渣的粒度比较均匀,且都在3 mm以下.以上参数能够对现场粒化液态钢渣起到实际的指导作用.     

螺旋槽干式气体端面密封的刚度和泄漏量研究

干式气体端面密封(DGS)是一种非接触式机械密封,适用于大多数气体密封场合,了解密封特性尤其是气膜刚度和泄漏量对正确设计密封非常重要.针对螺旋槽气体端面密封结构,用有限元法计算了密封端面的气膜压力分布及密封的气膜刚度和泄漏量等特性参数,分析了密封面的槽深比、螺旋角和槽长坝长比等两两变化时对密封特性的影响.研究表明,当槽深比取2.0～2.5,螺旋角取15°,槽长、坝长比取1.5～2.0,槽台宽比取1.0,槽数取12～18时,可在确保密封泄漏量低的同时具有较大气膜刚度.     

钢桶桶身翻边机原理应用

包装是产品的形象。综合服务处制桶厂生产的包装钢桶,不仅是玉门炼化总厂的产品形象,更是其产品质量保证的组成部分。一方面,钢桶外观一定要针对客户的需求,不断地改进;另一方面,低分子油品的超强渗透力要求钢桶的密封效果必须非常好,否则在油品贮存甚至装箱过程中就会出现油品渗漏和污染现象。所以,制桶厂在钢桶的制造过程中要不断改进其制造工序和工艺,而翻边作为其中的工序之一在其制造过程中起重要作用,于是该工序的工艺制作便成了钢桶质量的关键之一。     

MOS自动冲槽机控制器

本文介绍了把一台分立元件自动冲槽机控制器改为使用M0S集成电路的控制器的研制工作.主要工作是:据据MOS电路的特点设计了逻辑总图;设计和试验了合适可靠的拖板延时复位电路,单稳电路及功率驱动电路;装制了体积较小的控制器;“控制器”连续工作表明是稳定可靠的.一、概述现在的硅钢片冲槽机,大多数还是人工操作的,这不但效率低,也不安全.1977年初,我们参考了湘潭电机厂的晶体管自动冲槽机控制器的设想思想,根据我室生产的六种型号的MOS集成电路,设计和制造了MOS自动冲槽机控制器.该控制器是整个自动冲槽机的电子控制部分.它控制和协调冲槽机和机械手的工作,自动完成冲片上料,冲槽,下料等工作.实现了冲槽工序的自动化.控制器的基本设计思想是:按冲槽过程中各机械部件的动作次序及配合协调的要求,将动作分为若干个程序步(本机分为十个程序步),每个程序步完成一个或几个简单的机械动作,根据动作的时间长短,给每个程序步予置一定的时间,该时间一到则自动转到下一个程序步,每个程序步所发出的讯号由“记忆部件”记忆下来,并经功率门去控制继电器的吸合,从而控制各机械部件的动作.此外,为了保证冲槽机的动作的正确可靠和便于监视,还设置了显示部件、校验部件、互锁连锁电路以及报警系     

缩短合成氨原始开车过微量时间探讨

以煤为原料制造的合成氨原料气经脱硫、变换和碳化等净化处理后,仍含有少量CO、CO、HS和O等杂质气体。在原料气进氨合成工序前,必须使原料气中CO、CO含量(称为微量)小于25PPm,HS和O应完全除尽。本文就精炼工序采用醋酸亚铜氨液作为吸收剂清除原料气中少量一氧化碳等杂质气体(称为过微量)时,针对原始开车精炼工序工艺现状,探讨缩短原始开车过微量时间的方法。     

岩土勘察中的地基基础验槽工作研究

验槽工作是在建筑物基槽开挖后进行的一个重要环节,同时也是岩土勘察工作中的最后一道工序.本文首先说明了岩土勘察中地基基础验槽工作的目的,其次介绍了岩土勘察中地基基础验槽工作的具体步骤,最后介绍了岩土勘察中地基基础验槽工作的优势,进而为加强施工人员验槽工作技术提供参考.     

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。     

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.     

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