多跨转子不平衡载荷在线识别的一种新方法

本文基于转子一承系统的子结构模态分析及参数识别的方法，提出了一种旋转机械多跨转子不平衡载荷在线识别的理论方法。该方法为大型旋转机械转子失衡的在线监测提供了依据，并可用于转子系统的无试重动平衡。     

激励频率影响下的碰摩Jeffcott转子的非线性动力学行为分析

机械设计中为提高旋转机械的输出功率,采用的重要措施之一就是缩小旋转机械转子与静子之间的间隙,从而导致转静子间的碰撞与摩擦的可能性增大。所以大型旋转机械中动静件间碰摩是机组运行中常见的故障,主要发生在机组动静叶片密封、转子轴封以及滑动轴承等处。如果碰摩现象经常发生,使转子或叶片长期受到冲击作用,就有可能导致叶片的断裂,甚至引发其他严重故障,造成重大经济损失甚至人员伤亡。因此,通过试验探究转子系统碰摩发生的振动特征,特别是早期碰摩特征,并设法检测这些特征,对于转子系统避免碰摩故障及急发性故障的发生以及机组的良好运行无疑具有现实的意义。     

基于LabVIEW的多功能转子故障模拟测试系统设计

不平衡、不对中、弯曲、松动、碰摩等故障常导致旋转机械动态特性恶化。对转子振动信号的监测与分析,是判断设备故障类型及预测故障发展趋势的主要手段。本文开发出一种可实现故障模拟的多功能转子振动测试系统。通过改变轮盘的不平衡质量、调整轴承座的高度、控制润滑状态等方法模拟转子动平衡、不对中、轴承故障等多项实验。测试系统由转子实验台、传感器与信号调理设备、NI公司的6009数据采集卡及计算机组成。采用LabVIEW8．5设计了测试系统软件,详细讨论了转速、加速度及位移信号的采集与处理方法。测试结果表明,不同工作状态下轴承座振动信号的时域、频域波形和转子轴心轨迹形状可用于表征转子各单项及综合故障。     

烧结风机故障诊断应用

通过对烧结风机滑动轴承特性计算及从风机转子结构出发,建立风机转子-轴承系统的力学模型,用来校核系统的稳定性、分析影响稳定性的各种因素及查找风机系统存在振动问题的原因.同时应用旋转机械状态监测故障诊断CAMD-6100系统,对现场烧结风机进行监测,分析监测数据,最终找出故障原因,并加以解决.     

碰摩转子系统的混沌特性

基于旋转机械故障诊断的需要，分析了一个由油膜轴承支承的转子系统在转子与定子碰摩时的振动特征，模型考虑了碰撞时定子的线性变形以及摩擦时的库仑摩擦。分析表明，系统除具有各种形式的周期和概周期振动以外，还具有丰富的混沌运动与分叉现象。碰摩转子系统所展示的混沌运动以及所具有的各种现象，作为这类系统的显著特征，可以用于诊断汽轮发电机组中经常发生的碰摩故障     

旋转机械转轴裂纹损伤故障研究进展

综述了近年来旋转机械转轴裂纹损伤故障诊断研究的主要成果和发展前景。首先,对旋转机械转子系统转轴裂纹损伤非线性特性的研究方法、裂纹刚度模型和非线性动力学特性问题的国内外研究现状进行了概述。在此基础上,指出了目前旋转机械转轴裂纹损伤故障问题研究尚待解决的问题,并对今后的发展趋势进行了展望。     

转子系统非线性振动研究进展

由于机械运转速度的不断提高和新型材料、新型结构的推广应用,旋转机械的非线性动力学行为日显突出和重要基于线性系统原理的转子动力学理论与方法难以对实践中出现的丰富的非线性动力学现象作出准确的描述、阐释和预测近年 来,随着非线性科学研 究的深入和渗透,转 子系统非线性振动已成为应用力学和机械工程领域的研究热点之一从有利于建立旋转机械振动状态集与故障集之间的映射关系出发,综述了近年来转子系统非线性振动研究的主要进展,总结了转子系统中出现的典型非线性动力现象及其产生机理,目的在于丰富旋转机械故障诊断知识库参５５     

旋转机械基础松动故障研究进展和展望

基础松动故障是目前为止旋转机械故障中识别率较低的故障之一。对近年来旋转机械转子系统基础松动故障的研究现状、进展进行综述,包括基础松动故障非线性特性分析方法及复杂动力学特性、含有基础松动的耦合故障问题、基础松动故障诊断及故障试验等方面国内外的一些研究成果。在此基础上,对目前旋转机械基础松动故障问题研究尚待解决的问题提出了一些看法,并对今后的发展趋势进行了展望。     

非线性转子动力学问题研究综述

针对转子动力学中的非线性振动问题，综述了近年来国内外在该领域的主要研究成果和发展前景，首先，对转子动力学中非线性振动的类型及旋转机械设计方法的现状进行了分析，阐述了进行旋转机械非线性转子动力学研究的必要性，其次，综述了现代非线性动力学的理论分析方法及其在大型旋转机械应用方面、尤其是在转子－轴承系统非线性振动方面近期国内外研究工作的主要成果和进展，最后，对今后非线性转子动力学研究的趋势进行了说明和展望。     

旋转机械运行状态数据库的模糊聚类研究

旋转机械是化工、发电、高速运输工具动力系统的关键设备，为减少因定期维修或突发故障造成的经济损失，需对其进行实时状态监测，建立特定机组的历史故障或状态数据库。本文把旋转机械的振动频谱、润滑油温度等物理参量作为特征参量，利用模糊数学及多元分析原理对旋转机械状态监测系统数据库的建立进行了研究并将研究结果应用于实际机组，取得了很好的效果。     

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