基于遗传算法的双圆弧齿轮传动的神经网络优化设计

针对常规设计中双圆弧齿轮体积较大的问题,在先选定螺旋角的情况下,以圆弧齿轮传动的小齿轮齿数、法面模数及齿宽为设计变量,以两圆弧齿轮的体积之和最小为目标函数,应用遗传算法设计理论,建立双圆弧齿轮传动的遗传算法优化设计的数学模型,采用神经网络对其进行优化.结果表明,应用遗传算法和神经网络相结合的方法对双圆弧齿轮传动进行优化设计,可以克服单纯用遗传算法的早熟现象和神经网络发生局部收敛的缺点,体积减少30%以上.     

斜齿轮体积优化过程中建模方法的研究

针对目前齿轮体积优化设计中建模所存在的问题,以斜齿轮为研究对象,提出了斜齿轮体积建模的方法。首先分析了顶隙和变位系数对斜齿轮体积的影响,推导出由二者引起的间隙体积计算公式,以某斜齿轮为例,对间隙体积进行计算。结果表明,在齿轮体积精确计算等要求下,间隙体积不应忽略。其次,推导出不同结构下斜齿轮的体积计算公式,在Solidworks中建立相应的三维模型进行验证。最后,以斜齿轮设计参数为优化变量,以满足斜齿轮设计和传动要求为约束条件,以齿轮体积总和最小为优化目标,同时对需要查图表获得的参数进行公式化处理,利用MATLAB软件中的遗传算法工具箱进行优化,对优化结果进行标准化处理和圆整。以《机械设计》中某单级斜齿轮传动为例,利用上述方法进行优化设计,结果表明,优化后的齿轮体积减小了18.23%。     

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GDE混合算法的齿轮系统轻量化设计

基于某企业二级齿轮传动系统,对齿轮系统轻量化优化方法进行研究分析,提出一种基于遗传算法(GA)与差分进化算法(DE)的混合优化算法(GDE)。结合GA算法全局寻优能力强的特点,为DE算法提供优质初始种群,以二级齿轮中心距和体积最小为目标函数进行优化设计并将结果与两种传统算法结果进行比较,对轻量化后齿轮系统进行了模态分析。优化结果显示,GDE算法收敛速度最快,优化后齿轮体积减少了10.5%,重合度增加了5.8%;仿真结果显示,轻量化后齿轮不会产生共振,符合实际工况需求。     

基于均匀设计的遗传算法参数设定

在应用遗传算法进行优化计算时,各操作参数既有各自的功能又相互作用,彼此关系较为复杂,而各参数设定的好坏直接影响算法的性能,所以,各参数的设定是应用遗传算法进行寻优计算的重要问题·通过对遗传算法各操作参数作用与意义的分析,认为可以将遗传算法的参数设定描述为一个多因素多水平优化设计问题·为使遗传算法在应用中发挥最佳的寻优性能,同时考虑到参数设定方法的可行性,提出应用解决多因素多水平优化设计问题的均匀设计方法设定遗传算法的操作参数,实例应用仿真结果验证了这种方法的可行性、有效性·     

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．     

采用多准则决策分析的高功率微波源多目标优化设计

为解决高功率微波源优化设计难度较大的问题，将多准则决策分析方法、遗传算法和全电磁粒子模拟软件UNIPIC相结合，提出了一种适于高功率微波源的多目标优化设计方法FSAWS-GA。通过对待优化器件的结构参数进行浮点编码生成种群个体，利用多准则决策分析方法中的主观目标和客观目标评价算法实现个体适应度评价，基于遗传算法实现种群进化，达到高功率微波源多目标优化设计的目的。对比测试结果表明：FSAWS-GA算法较传统单目标遗传优化算法，对高功率微波源优化有更好的适应性，能够优化出多性能指标均符合设计要求的器件结构。利用FSAWS-GA对一种Ka波段的相对论返波管进行了结构优化测试，得到了输出功率为0.642 GW、工作频率为26.68 GHz、频率纯度为0.09、电子通过率为86.72%、能量转换效率为15.6%的新型器件结构。新型器件结构在确保多项性能指标均满足设计要求的前提下，输出功率较原器件提高了210.1%,验证了利用FSAWS-GA算法实现高功率微波源多目标优化设计的可行性。     

基于传动链仿真的发电机智能反演优化设计

提出了一种针对运行在传动链系统中的发电机智能反演优化设计方法,并以一台运行在传动链系统中的15 kW永磁同步发电机为研究对象,针对其运行效率对发电机的设计参数进行优化.首先,在充分考虑变流器侧对整个传动链系统的影响下,建立了面向传动链系统的协同仿真建模平台,验证了传动链的电磁设计参数与协同仿真计算平台的正确性;其次,通过方差分析从发电机的8个设计参数中选定6个敏感参数,并在选定优化变量后提出了一种基于遗传算法优化的拉丁超立方抽样方案,该抽样方案可以兼顾样本空间均匀分布与各变量维度投影的均匀性;然后,通过基于高斯随机过程的智能反演优化设计模型结合基于范围选择的多目标优化算法,获得发电机的效率与最大额定输出转矩的Pareto前沿,并针对优化后的齿槽参数进行绕组设计,结果显示优化后的效率为96.2%,对比其原始设计方案,发电机电磁损耗降低了16.8%,效率提高了0.6%; 最后,通过实验验证了仿真平台的准确性,进一步说明了样本数据与优化设计的有效性.所提设计方法可针对不同规格的大型传动链系统展开优化设计,其优化方法具有一定的普适性,可用于我国海上大型传动链系统的一体化精确仿真计算与流程化优化设计.     

基于粒子群算法的行星齿轮传动设计与优化

根据给定的行星齿轮初始条件,本文按照传统设计方法及国标标准设计NGW型行星齿轮传动机构.为改善行星齿轮在传统设计中的复杂算法及不能使目标函数达到最优等问题,采用粒子群优化算法建立行星齿轮传动的优化设计模型.该粒子群优化算法是一种基于MATLAB编程的进化算法,采用粒子群优化算法对经过传统设计的行星齿轮体积进行最小值优化...     

摆线针轮行星减速器最佳短幅系数的确定及优化

短幅系数是摆线针轮行星减速器的重要设计参数,它直接决定着减速器的性能.针对目前设计中短幅系数往往由经验选取的问题,提出了以单参数最大效能体积比来确定最佳短幅系数的方法.并基于遗传算法对摆线针轮行星减速器进行了优化设计,得到了良好的设计结果.通过实例说明研究结果具有一定的理论和应用价值.     

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