基于RecurDyn的带式输送机启动性能影响因素分析

带式输送机的启动性能会受输送距离、拉紧力和工作平面倾斜角度等因素的影响.为实现各影响因素的优化组合以提高启动性能,利用多体系统仿真优化软件RecurDyn建立了不同结构参数和拉紧力的带式输送机仿真模型.通过仿真分析得到了各个模型的启动时间和输送带所受拉伸力仿真结果,并同理论计算值进行对比.结果表明:适当改变结构参数和增大拉紧力能够提高带式输送机的启动性能.     

三维离散元法软件开发研究

提出由机械部件的CAD模型建立其三维离散元法分析模型,在此基础上实现CAD软件与自主研制的三维离散元法分析软件的集成,从而构建一种集设计和性能分析评价为一体的与散粒材料接触作用的机械部件的通用数字化设计方法和集成设计分析软件,为相关机械部件结构和尺寸参数的优化设计奠定了基础.介绍了自主研制的三维离散元法分析软件的结构、主要功能及关键技术的实现方法,包括提出的实边界和虚边界的概念等.     

集成化钢管成型机的设计

为设计一台高集成化的钢管成型机,用塑性有限元软件Dynaform对钢管在不同壁厚情况下的弯曲过程进行模拟,确定其结构参数对构件成型的影响,为构件、模具及机器设计提供依据.利用Creo软件进行模具建模,再通过Creo与CAD软件进行装配验证各设计尺寸的配合.在钢管成型机机械结构上设计了料斗、导料组件、工作台、机架、导流板,通过Creo与CAD软件设计零部件结构和装配结构,设计的液压传动系统,将自动上下料直至钢管成型等工序集成在一台机械上.经样机测试,该钢管成型机可以满足工作可靠、操作方便快捷、生产效率高的生产要求.     

尺寸公差标注的计算机辅助设计

本文介绍尺寸公差标注的CAD软件.该软件是对Auto CAD系统的二次开发.扩充了Auto CAD的性能.     

基于ANSYS的槽式太阳能桁架支撑结构数值分析

利用ANSYS有限元软件建立模型,根据桁架式聚光器的实际工况进行结构静力学仿真分析,并对该模型进行模态分析研究,得出影响聚光器结构和工作性能的共振频率值.同时应用ANSYS优化模块对桁架杆的尺寸进行优化,在满足设计要求的范围内,使桁架式支撑结构的重量达到最优值,既能实现产品正常性能,又能降低企业生产成本.     

带式输送机液压自动拉紧控制系统

介绍了大型带式输送机张力自动调节的必要性,阐述了带式输送机张力液压自动调节装置的调节原理,设计了一种新型的带式输送机张力的液压自动拉紧系统,分析了拉紧装置的特性并构造了拉紧系统的传递函数,在此基础上构建了使用这种控制系统的带式输送机的动力学模型和数学模型.并利用该模型分析了输送带张力自动控制过程,用实例分析了张力自动控制系统的性能,应用simlingk软件进行了系统仿真,结果证明这种液压自动拉紧系统具有较好的适应性和稳定性.     

基于PROE的箱型步进梁有限元分析

以金川阴极铜板自动包装生产线出料机步进梁为研究对象,首先利用大型三维软件PRO/E对步进梁进行三维CAD建模.然后通过有限元分析软件ANSYS对建立的模型进行网格划分.最后在四种不同工作状态下对步进梁结构力学性能进行分析,得到步进梁在工况二时出现最大变形与最大受力.将有限元仿真分析运用到工程技术领域,为解决同类问题提供了理论依据及参考.     

带式输送机停机动态过程的计算机仿真

研究了带式输送机停机过程的动态设计,通过分析提出了输送机停机过程的力学模型为两种:第1模型与启动过程的力学模型相同,第2模型为具有固定端的振动模型·分析了制动力的传动机理;在综合各种停机方式的基础上给出了停机过程的分类,提出了控制速度停机、自由停机和制动停机的计算方式及其计算方法;开发了带式输送机动态分析软件BCD.20的停机计算部分;应用软件对停机过程进行仿真研究,对停机过程进行了分析;给出了停机过程的动态设计方法和拉紧装置行程的计算式;得出了不同的停机方式结束后输送带的张力分布是不同的结果·所提出的方法可用于大型带式输送机停机过程的合理设计,避免事故的发生     

基于ANSYS的物料车车架的有限元静态分析

对物料车车架有限元模型进行静态强度分析.应用三维绘图软件Solid Edge建立车架结构的CAD模型,并通过工程分析软件ANSYS11.0进行网格划分和静态强度分析,获得物料车在不同工况下车架的变形量和载荷强度,校核该车架强度是否满足要求.     

加热炉钢结构中型钢标准件的生成方法

加热炉钢结构装配体在生成过程中需要大量重复使用型钢标准件,缩短标准件的生成时间成为设计者所关心的问题.针对型钢的结构特点,基于Solid Edge软件,将零件族设计思想应用于型钢标准件设计,使用参数信息表对型钢标准件进行整理和归类,在共享主体模型的基础上,通过特征组合和尺寸变化实现了指定规格型钢结构的快速生成.该方法同样适用于其他CAD平台标准件库的建立,可以缩短设计周期,大幅度提高设计效率.     

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