弹性连杆机构频率分析中的一个理论问题

通过实例从理论上阐明了在弹性连杆机构ＫＥＤ分析中关于悬臂梁假的力学含义，澄清了概念，以消除人们对此问题的误解。     

连杆机构运动弹性动力分析的直接积分法

采用直接积分法确定弹性连杆机构的稳态响应．从而避开了弹性连杆机构ＫＥＤ分析过程中求解特征值问题．这不失为一种直接获得弹性连杆机构动态响应和机构真实运动轨迹的迅捷方法．并从能量考虑讨论了算法的稳定性．     

回转键合图法弹性连杆机构动态仿真

本文较详细地给出了弹性连杆机构动态仿真的回转键合图法,给出了一般弹性连杆机构的键合图模型,在此基础上推导出了便于求解的刚、弹性连杆机构状态方程的统一表达式。用本方法所编制的计算机程序,可以格式化的方式在计算机上自动建立机构(弹性、刚性)的状态方程并求解。最后用实例来说明本文方法及程序的可靠性及通用性     

弹性连杆机构的时域子结构综合方法

提出了一种弹性连杆机构稳态动力响应的时域子结构综合法。该方法直接在子结构水平上计算弹性连杆机构稳态动力响应,因而能大幅降低机构运动弹性动力学方程求解规模。文中给出的数值算例说明了方法的有效性。     

电机—弹性连杆机构系统的动力学分析

为了提高机械的设计精度,优化机构的动力学响应,研究了电机－弹性连杆机构系统,对系统进行动力学建模,将整个系统分成电机和弹性连杆机构两个子系统,对各个子系统分别建模,再综合得到系统的动力学微分方程,对该方法求解,推导了一种适合于求解用精确分析方法得到的弹性连杆机构动力学方程的迭代振型叠加法,通过实例计算,研究了系统中弹性宫杆 动力学特性,得出一些有益的结论。     

平面连杆机构 KED 分析的新方法

将弹性连杆机构的构件视为质量连续分布的弹性体，依据弹性体振动理论求解机构的固有频率、主振型及ＫＥＤ响应。与有限元法相比，本方法模型精确、概念清晰简明，计算精度和速度得到提高     

关于提高弹性连杆机构动力分析计算效率的若干问题

本文以文献提供的方法为依据,进行了大量的计算工作,在计算中通过反复实践,对如何提高弹性连杆机构的计算效率与精度提出了几点措施。恰当地实施这些措施可显著提高弹性连杆机构动力分析的计算效率。     

基于最优极点配置复合控制的弹性连杆机构主动控制研究

采用最优极点配置复合控制策略对高速弹性连杆机构的振动主动控制进行了研究。基于机构弹性动力学分析（KED）建立了受控系统状态方程，讨论了系统最优极点的选取方法。对一个具有弹性连杆和摇杆的四杆机构进行数值仿真的结果表明，最优极点配置复合控制对弹性连杆机构振动响应具有明显的抑制效果。     

再论弹性连杆机构的低阶谐振现象

根据振动理论，从动力学的角度，对弹性连杆机构的低阶谐振现象重新做了解释。认为弹性连杆机构的低阶谐振现象实际上是机构的一种复杂的共振现象，并且提出了避免产生低阶谐振现象的措施     

弹性连杆机构曲柄参数对电动机转速的影响分析

分析了弹性连杆机构曲柄参数与机构基频的关系,通过由基频引起的弹性振动对电动机转速的影响进而分析了曲柄参数对电动机转速的影响,并通过一个曲柄连杆机构实例进行了数值分析,这一结果对高性能机构设计有一定的指导意义。     

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