磁盘高点的铲刮及其铲刮头静特性的实验研究

：阐述了磁盘高点的形成及其铲刮技术，并着重论述了铲刮头的静特性设计和实验研究。铲刮是用超硬材料制成的铲刮头浮动块去碰撞磁盘表面上的高点来完成的。铲刮头分为正压型与负压型两种。文中分析计算了这两种铲刮头的静特性。实验表明，这些铲刮头在磁盘表面上可以稳定地浮动，其头盘间隙可控制在 ０．１～０．２μｍ。它们可以高效地铲刮高于 ０．２ μｍ的高点。     

地效翼船纵向稳定性与操纵性研究

纵向稳定性一直是地效翼船发展中面临的问题之一．以状态方程作为描述地效翼船的数学模型,研究了地效翼船在飞行状态下的纵向操纵性与稳定性．根据特征方程常数项系数,直接判定静稳定性,分析了主要气动导数对静稳定性的影响,认为Ｃｍｚ取接近于零的正数既有利于静稳定性又能简化静稳定性的判定条件．根据特征根,判定动稳定性,作出模态矢量图,并分析了三个模态的主要特性以及状态变量在各模态中的反映;分析了在从自由空间到地效区的过渡区域,忽略速度变化的四阶运动方程所得的动稳定性与五阶方程所得的动稳定性不一致的原因,指出在这一区域尤其要注意四阶方程的有效性．最后,从现代控制理论的角度提出纵向操纵性的研究思路     

厚壁圆柱结构振动

对于长而厚的圆柱结构，由于其巨大的应用潜力以及日益严格的使用要求，近年来发展了关于厚壁圆柱结构振动与被动振动控制相关问题的研究。圆柱结构振动研究的重要步骤是其振动模态特性的确定。模态信息对于动载荷激励结构的设计与振动控制具有重要的作用。目前关于圆柱结构动态响应的研究都基于壳理论，     

触头系统在任意力函数作用下的响应分析

对直动式交流接触器中的触头系统在动、静铁心吸合过程中所引起的两次振动就其振动特性和系统响应进行了初步分析与研究、得出了触头系统的响应规律及动触头的最大弹跳量和衰减情况。通过实例计算，结果与文［３］的实测相一致．     

混流式转轮静强度和振动特性分析

为大型水轮机组的安全、稳定运行,研究了转轮在水介质中的动力特性。运用顺序耦合的方法,分析了在三维旋转流动所产生的水压力作用下转轮体的静强度特性;运用全流固耦合的三维有限元方法进行了转轮在水介质中的模态分析。强度分析结果表明,应力集中的部位与裂纹实际产生的位置完全吻合,但最大等效应力远小于材料的极限破坏应力;模态分析得到转轮在水中的自振频率和振型等振动特性,指出了发生共振的可能性。结果证实了导致裂纹产生的原因不是静应力而是动载荷的作用。     

车床刀架系统动力设计

对Φ４００普通车床的刀架系统进行了动态特性研究，以主要模态柔度及各阶模态能量分布为判据，进行了动力修改设计，获得较高的静、动态特性。     

复合棒压电纵向振动换能器中的弯曲振动

采用有限元方法，研究了复合棒压电纵向振动换能器前辐射头两端自由及小端面中心固定时的弯曲振动模态及与几何尺寸之间的关系；探讨了换能器多模振动特性与前盖板几何尺寸之间的变化关系．结果表明，换能器前两个频率间距取决于前盖板前端直径与前盖板厚度之比，比值变大，两频率间距变小；比值变小，两频率间距将会拉大．     

精密镗削头振动模态的实验研究

通过对国产与进Ｄ的同类型精密镗削头振动模态实验研究，找出了这两种精密镗削头的固有振动频率，给出了它们的各阶动画振型图．从这一侧面解释了国产精密镗削头回转精度偏低的原因。     

圆柱壳结构振动特性研究

利用有限元法研究了圆柱壳结构的振动模态特性，分析圆柱壳结构参数对振动模态的影响，数值计算结果表明，随着管道直径的增大，模态密度会增大，并且周向频率存在着置换性等特点。研究得到的圆柱壳结构的周向和轴向模态的变化规律，为管道系统的动态可靠性设计提供理论依据，     

汽轮机末级叶片振动特性研究

建立了汽轮机末级叶片的三维有限元模型,分析了叶片的静频和振型,然后计算了叶片在预应力条件下的动频,分析了工作转速对叶片振动特性的影响.最后在振动试验台上开展了叶片静频、动频和振动响应试验,实验结果与数值模拟吻合较好.研究结果表明:叶片的动频比静频大,且动频随转速的增加而增大;转速对低阶频率影响较大;在转速的9倍频激励时发生二阶共振,叶片易产生振动疲劳失效.     

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