基于UG-NX6的渐开线斜齿圆柱齿轮参数化设计研究

渐开线斜齿圆柱齿轮齿形轮廓复杂,其参数化设计困难.利用三维软件UG-NX6对斜齿圆柱齿轮进行三维建模,实现了改变参数就立即得到相应的渐开线斜齿圆柱齿轮三维模型的参数化设计.对其他具有复杂表面形状的形体参数化设计提供了参考.     

标准斜齿圆柱齿轮螺旋角的测绘

修配单个标准斜齿圆柱齿轮，在没有图纸和必要的参数的情况下首先要确定其法向模数mn，并测定齿顶圆尺寸da，螺旋角β才能根据（1）式确定。标准斜齿圆柱荫轮法向模数mn的确定，其方法与直齿圆梓齿轮基本相同。     

基于复合—遗传算法斜齿轮减速器优化设计

针对标准复合形算法在设计变量较多时容易陷入局部最优的缺点,提出了复合形—遗传算法.建立了两级斜齿圆柱齿轮减速器的结构参数优化模型,并开发了相应的计算程序.以齿轮中心距之和为优化目标,在所确定的约束条件下,采用复合形—遗传算法对两级斜齿圆柱齿轮减速器进行结构参数优化设计.结果表明,减速器原方案并不是最优方案,尚有较大的优化空间,同时优化结果也证明该优化设计方法的可行性.     

基于复合一遗传算法斜齿轮减速器优化设计

针对标准复合形算法在设计变量较多时容易陷入局部最优的缺点,提出了复合形一遗传算法．建立了两级斜齿圆柱齿轮减速器的结构参数优化模型,并开发了相应的计算程序．以齿轮中心距之和为优化目标,在所确定的约束条件下,采用复合形一遗传算法对两级斜齿圆柱齿轮减速器进行结构参数优化设计．结果表明,减速器原方案并不是最优方案,尚有较大的优化空间,同时优化结果也证明该优化设计方法的可行性．     

时变啮合刚度作用下直齿与斜齿圆柱齿轮的振动特性分析

作为传递动力与能量的关键部件,齿轮系统在石油石化装备中有着十分广泛的应用。针对常用的直齿与斜齿齿轮传动系统,分别利用能量法与累计积分能量法建立了直齿与斜齿圆柱齿轮齿的变截面悬臂梁模型,对比分析了直齿与斜齿圆柱齿轮系统时变啮合刚度的基本特性。利用集中参数法,分别建立直齿与斜齿圆柱齿轮齿的弯扭耦合振动模型。利用Nemark-β数值积分法对模型进行了仿真求解,对比分析了时变啮合刚度作用下直齿与斜齿圆柱齿轮系统的振动特性。结果表明:直齿圆柱齿轮时变啮合刚度存在阶跃性突变,而斜齿圆柱齿轮时变啮合刚度波动较为平稳。由于直齿圆柱齿轮时变啮合刚度的阶跃性突变,直齿圆柱齿轮的振动幅值与冲击响应要远远大于斜齿圆柱齿轮。本文阐明了直齿与斜齿圆柱齿轮在时变啮合刚度及振动响应上的异同点,从动力学分析的角度揭示了斜齿圆柱齿轮系统传动平稳的内在机理,可为齿轮传动系统的减震降噪及结构优化提供理论基础。     

基于Pro/Engineer的斜齿轮参数化设计

针对渐开线斜齿圆柱齿轮齿廓形状复杂,设计周期长的特点,基于Pro/Engineer Wildfire 2.0平台,利用关系式(relations)和程序(program),通过修改齿轮的特征参数,驱动齿轮的快速再生,实现了渐开线斜齿圆柱齿轮的参数化设计,提高了设计效率.     

基于UG的渐开线直齿圆柱齿轮建模研究

摘 介绍了使用UG／OPEN API实现渐开线直齿圆柱齿轮的模块的开发过程,并结合UG／OPEN GRIP开发渐开线直齿圆柱齿轮的方法,这个方法成功设计出参数化渐开线直齿圆柱齿轮的模块。     

基于参数化技术的圆柱直齿斜齿统一建模方法

运用参数化建模思想,提出了一种统一斜齿、直齿圆柱齿轮的三维建模方法;并且使用Pro/E 2.0实现了所提出的统一建模方法.运用该方法通过给参数赋不同的值就可生成相应的直齿、斜齿圆柱齿轮;该方法可加快齿轮类零件的三维建模进度,为后续机构运动学、动力学仿真分析及零件数控加工提供基础数据支持.     

基于Pro/E的渐开线齿轮参数化设计系统的开发

介绍了在Pro/E环境下,运用圆柱坐标系创建渐开线圆柱齿轮齿廓,利用其开发工具参数(Parameters)结合关系式(Relations)功能来实现渐开线齿轮参数化造型的关键技术;并在研究了Pro/Toolkit特征建模编程原理的基础上,以VC++6.0作为编程语言,实现了利用友好的图形用户界面技术输入设计参数来控制三维实体模型的关键技术。该文以开发渐开线齿轮参数化设计系统(本系统涵盖了直齿、斜齿、蜗轮、蜗杆、锥齿)为实例,详细介绍了这一开发思路和其关键技术。     

基于Pro/E的渐开线齿轮参数化设计系统的开发

介绍了在Pro/E环境下,运用圆柱坐标系创建渐开线圆柱齿轮齿廓,利用其开发工具参数(Parameters)结合关系式(Relations)功能来实现渐开线齿轮参数化造型的关键技术;并在研究了Pro/Toolkit特征建模编程原理的基础上,以VC++6.0作为编程语言,实现了利用友好的图形用户界面技术输入设计参数来控制三维实体模型的关键技术.该文以开发渐开线齿轮参数化设计系统(本系统涵盖了直齿、斜齿、蜗轮、蜗杆、锥齿)为实例,详细介绍了这一开发思路和其关键技术.     

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