基于Pro/E的齿轮三维参数化造型系统设计

基于Pro/E平台对渐开线齿轮的齿廓构成特征进行分析,阐述了渐开线齿轮造型系统的设计过程.此系统能够快速地实现齿轮的参数化造型设计和修改定型,同时也解决了渐开线齿轮精确造型的难题.     

关于渐开线齿轮传动噪声的探讨

对渐开线齿轮噪声产生的原因进行了一些探讨,提出了具体的降噪措施,以降低渐开线齿轮的噪声。     

渐开线外齿修缘插齿刀的设计

目前,越来越多的渐开线齿轮齿顶要求修缘,这样有利于提高啮合质量。因此,用修缘插齿刀来加工需要修缘的齿轮是一种很有效的加工方法。分析了渐开线外齿修缘插齿刀的设计,给出了具体的计算方法。     

渐开线齿轮动态啮合力计算机仿真

为了获得渐开线齿轮啮合传动过程中的动态啮合力,提出了一种在MSC-ADAMS平台上的计算机仿真方 法．考虑了齿轮高速、大转矩啮合传动以及渐开线齿轮工作过程中齿廓啮合点位置不断变化的实际情况,基于 Hertz弹性接触理论,建立了仿真用齿轮刚度系数的计算公式及渐开线齿轮啮合传动的仿真模型,并以某车用变速 器的一对渐开线齿轮为研究对象,应用机构动力学仿真分析软件,计算得到了在3种不同工况下的齿轮动态啮合 力．研究结果表明:渐开线齿轮在啮合传动过程中含有明显的动载荷,动载荷的波动并非对称循环,其均值大于静 载荷;随着传动速度的增大,动载荷及其作用时间所占比例均增大．     

基于 VB 的渐开线齿轮参数计算机辅助设计

本文采用Visual Basic为编程语言,以ACCESS为数据库,设计出了渐开线齿轮参数辅助设计系统,该系统对于渐开线齿轮的设计有一定的实际意义.     

基于正弦齿条的齿轮及其齿廓曲线

提出一种以正弦曲线为生成齿条的齿廓曲线生成的新型齿轮.与渐开线齿轮的生成齿条不同,正弦齿条的设计压力角与轮齿高度、厚度之间具有一定的关系.设计压力角增大,则轮齿高度减小、厚度增大.通过齿廓图形仿真发现,正弦齿条生成的齿轮发生根切的倾向明显小于渐开线齿轮.所生成齿轮的齿廓与双圆弧齿轮相似,因而接触强度和弯曲强度要高于渐开线齿轮.文中给出了正弦齿廓在椭圆传动中的应用,并附加相同设计参数的渐开线齿轮传动情形以作对照.     

减速式同步电动机的基本理论

在许多自动化装置中,往往需要低转速大转矩驱动。过去常用电动机加齿轮减速,由于齿轮减速带来许多缺点,有时不能满足要求。减速式同步电动机是最近发展起来的一种低速电动机,它是利用气隙磁导波而工作的新型低速电机。在工频50赫电源下,不需齿轮减速,可以直接得到每分钟60转或更低的转速。由于没有高速转动部分,取消了齿轮传动,可以简化传动机构,提高整个装置工作的精度和可靠性,消除由于齿轮传动引起的噪音,维护简单,并可提高使用寿命。对那些要求减小电气装置的重量和体积而提高电源频率的埸合,采用这种电动机更有重要意义。由于电动机的瞬时转速稳定度很高,因此特别适用于那些要求瞬时转速稳定的埸合。在电动执行机构、机床自动化、计测装置、传真及低温装置等方面有广泛的使用前途。本文着重分析这种电动机的基本理论,关于它的设计方法将另文讨论。     

斜齿轮插齿刀计算机辅助设计研究

插制渐开线斜齿轮的加工是一种空间啮合的加工方式,计算过程非常复杂。文中提出加工渐开线斜齿轮插齿刀的程序化设计方法及实现。     

用于齿轮齿面形状误差测量的光学系统设计与仿真

基于齿轮齿面的特殊性和激光干涉系统设计理论,以系统易实现、且能获得良好的干涉条纹图像为具体设计目标,提出了斜入射式的激光干涉测量系统结构方案。介绍了光学测量系统的结构、原理,阐述了基于光线追迹的光学系统计算仿真方法,给出了分别以平面、渐开线直齿轮齿面和渐开线斜齿轮齿面作为被测对象时的干涉条纹图像的仿真结果。     

基于UG渐开线圆柱齿轮三维模型参数化设计

渐开线圆柱齿轮包括常见的圆柱直齿轮和圆柱斜齿轮,本文通过研究在UGNX6中对渐开线齿轮进行统一参数化数学建模方法,实现渐开线齿轮的参数化设计过程,提高了齿轮设计工作的效率.     

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