基于AutoLISP的四连杆机构运动轨迹分析及应用

四连杆机构在机械工程的运动机构设计中得到广泛采用。本文介绍并运用AutoLISP程序设计语言对四连杆机构运动轨迹进行了描述,从而体现出AutoLISP人工智能绘图语言的特点。     

支撑掩护式液压支架的优化设计

为了提高液压支架顶板管理以及承受较大载荷的能力,必须使液压支架顶梁前端的运动轨迹为水平摆幅最小的近似双扭线。通过对液压支架四连杆机构的运动特性分析,建立了四连杆机构的优化设计数学模型,基于遗传算法求出了使顶梁前端运动轨迹为近似双扭线,且双扭线水平摆幅e最小时的各杆长度及相应参数,并以ZY35型液压支架的设计为例进行了验证。结果表明:利用遗传算法对液压支架四连杆机构进行优化设计可以得到理想的设计参数,生产的液压支架工作状态平稳,支护效果良好。     

关于平面、空间四连杆机构位形矢量解的讨论

本文采用矢量分析的方法,对平面四连杆机构OPQR,空间四连杆机构R-G-G-R和空间机构H-R-G-R的位形矢量解作了进一步的讨论,给出上述机构位形矢量解的取值规律,并附有形象化的平面、空间几何图解。     

建筑幕墙开启窗平面四连杆机构动态模拟及实现

针对建筑幕墙开启窗平面四连杆机构的连杆曲线推演计算不直观的问题,推导出平面四连杆机构各连接点和连杆曲线轨迹点的坐标公式,开发了连杆曲线计算机动态模拟程序,并绘制出程序流程图和界面。为工程技术人员提供了一个简洁绘制、查阅连杆曲线的思路。     

四连杆机构的运动设计

Ⅰ.前言在现代机器中,低副平面机构仍然占有重要的位置,而在低副平面机构中,使用最多的还是二级机构和三级机构。本文只研究二级机构的运动设计问题。在二级机构中,也可能包含很多的的构件,本文只研究二级机构中最基本的,但是最重的四连杆机构,即包含一个原动件,一个二级组和固定件的机构。因为最复杂的二级机构事实上就是最基本的四连杆机构上再加上若干个二级组成功的,其设计方法和基本的四连杆机构的设计方法完全相同。     

以运动平面上瞬时加速度中心设计平面四连杆机构

本文运用几何学中完全四边形的密克点概念来求取运动平面瞬时加速度中心。并以实例介绍如何由瞬时加速度中心来综合设计平面四连杆机构的方法     

矢量对方法综合曲柄滑块机构

本文在用矢量对的方法综合平面铰链四连杆机构的基础上,提出了综合曲柄滑块机构的矢量方程。用这一方程可解决综合曲柄滑块机构实现刚体导向的问题。     

平面机构运动传递指数的分析

从简单的四连杆机构入手，分析了速度矩阵与死点位置的关系，指出死点位置的运动特殊性．将其结论推广至属于Ⅱ、Ⅲ、Ⅳ的平面六杆机构．并给出运动传递指数的概念，用以评价平面六杆机构的传递性能     

广义质量静替代计算公式的探讨

在本文中,用“广义质量”或复数形式的质量来代换平面运动连杆中的集中质量时,可得到如下结论:1.存在某种代换,使得平行四连杆机构的集中质量变为完全等效的广义质量。2.存在某种代换,使得四连杆机构的集中质量变为等效但非完全等效的广义质量。     

NF无梭织带机引纬机构的运动分析

NF无梭织带机引纬机构是由一组平面四连杆机构与一组空间RSSR机构组合而成。本文运用复数矢量法、坐标变换法分别对其平面机构、空间机构作了运动学解析,建立了适于计算机求解的数学模型。文末还给出了其数值计算结果。所得结论对生产厂、使用厂均有一定的指导意义。     

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.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the     

An affordable accurate evaluation of the binding conformations predicted by molecular docking studies in bio-system

Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of     

Call for Papers

<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with