考虑间隙时初轧机扭矩放大系数的确定

初轧机主传动系统中的万向接轴,由于磨损常存在较大的间隙,在咬钢时就会发生撞击。因而引起主传动系统的较大幅度的扭振。这就可能成为零件疲劳破坏的因素。本文将探讨考虑间隙情况下初轧机主传动系统扭振时确定扭矩放大系数的方法。     

连轧机万向接轴集油盒损坏机理

运用遥测系统对轧机扭振和轴向振动做了现场综合测试和信号分析,利用ANSYS软件中谐响应模块进行计算机仿真研究.结果表明:轧机万向接轴轴向振动导致了万向接轴上的集油盒轴承频繁损坏,同时发现集油盒轴承的轴向振动是由电机轴的扭振产生的,即万向接轴的轴向振动是由主传动系统的扭振引发的.通过改进集油盒轴承结构,使轴向振动承载能力提高,大大延长了集油盒轴承的使用寿命.     

轧机主传动万向接轴随机疲劳设计

万向接轴是轧机主传动系统的关键部件,具有结构复杂、工作时承受随机冲击扭矩等特点.在分析轧机主传动万向接轴受力特点的基础上,提出应以轧机冲击扭矩载荷谱作为主传动万向接轴的疲劳设计载荷;计及低于疲劳极限的应力循环对裂纹发展的影响,采用修正后的材料p-S-N曲线并运用累积损伤理论对万向接轴进行随机疲劳设计和寿命预测.提出的轧机主传动万向接轴随机疲劳设计方法同样适合于具有同类载荷特征机械零件或结构的疲劳设计.     

1150初轧机万向接轴扁头断裂分析

本文通过对初轧机万向接轴材质35 CrMOV钢K_(IC)和K_(Id)值的实测,计算了扁头裂纹尖端的应力场强度因子,应用断裂K判据,分析扁头脆断的原因.结果表明,由于初轧机上轧辊在强烈扭振和冲击载荷作用下,导致了扁头的断裂.     

立辊轧机主传动系统的扭振研究

通过理论和实测相结合的方法，对４２００立辊轧机主传动系统进行分支闭合系统的扭振分析，发现了两辊轧制时出现负力矩的原因。结果表明：理论计算与现场测试是一致的。     

热连轧机水平振动仿真与实验研究

某热连轧机在轧制薄规格板材时发生强烈振动,为确定其振动类型和振源,对其进行仿真计算和测试分析。首先计算该轧机水平振动和主传动系统的固有频率和主振型;然后对该轧机主传动系统和辊系振动情况进行综合测试,发现该轧机水平振动最剧烈,并引起轧机垂直振动和主传动系统扭振,因此,对该轧机水平振动进行仿真分析,研究轧件厚度以及工作辊和支承辊偏移量对水平振动的影响。研究结果表明:轧件厚度越薄,后张力和轧制力的波动越大,对轧辊水平振动影响增大;工作辊与支承辊偏移量的增大,轧机水平振动降低,达到稳态振动的时间缩短,但该偏移量不宜过大。增加0.7 mm厚垫片减小工作辊水平振动的方案,可以减小间隙,明显抑制轧机水平振动,效果良好。     

考虑带钢的轧机主传动系统扭振数值研究

带钢作为连接各机架间主传动系统的纽带,其动力学特性决定着主传动系统扭转振动的动态性能。因此,考虑带钢连接的轧机主传动系统扭振模型的研究十分必要。利用ANSYS软件,建立带钢连接的双机架主传动系统有限元实体模型,并对其进行模态分析。然后对带钢施加变频力进行谐响应分析,得到各机架主传动系统中不同部位角位移随频率变化的规律曲线。最后通过对比谐响应分析与模态分析结果,进一步研究带钢与轧机主传动系统扭振之间的固有属性关系。     

冲击扭振下初轧机扭矩放大系数的确定

初轧机咬钢时会受到很大的冲击载荷,从而引起传动系统的扭转振动。如果系统配置不当,系统内会产生很大的扭矩,使部件破坏。因此研究主传动系统扭振时扭矩放大系数有重要意义。     

φ1150初轧机主传动系统扭振研究

在现场综合测试的基础上，分析了采用可控硅供电的１１５０初轧机主传动系统的扭振状况。应用作者建立的有阻尼原坐标分析法，对主传动系统的扭矩响应波形进行仿真，结果与实测波形一致。这为轧钢机主传动动态计算提供了一种新的方法。     

设计参数对2300轧机主传动系统扭振固有频率影响的灵敏度分析

研究了轧机主传动系统扭振固有频率的影响因素，给出了固有频率相对设计参数变化的灵敏度计算公式，用所编制的计算机程序，对2300轧机主传动系统的固有频率影响因素的关系进行了分析与计算。     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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