基于最小材料去除量的比较球面计算与仿真

基于非球面最接近球面的计算方法分析,构建成型设备与工件间坐标变换矩阵,借鉴并优化材料去除量最小原则,计算最接近球面与理论非球面间的偏离量,建立数学模型.针对典型的圆形口径和矩形口径同轴、离轴非球面元件的比较球面求解进行仿真.结果表明,所建立的数值求解模型可有效计算同轴、离轴非球面元件的比较球面使材料去除量最小,对加工实践起到指导作用.     

波像差法构建非球面干涉检测的误差分离模型

非球面元件光学干涉检测中,获得客观、准确的面形信息是实现元件快速、确定性制造的关键因素之一。为了实现大口径光学离轴非球面反射镜的高精度检测,对其干涉检测结果中的误差信息表现形式进行了分析研究,提出了一种基于将离轴非球面反射镜检测工装视为具有5维自由度空间刚体设想的误差分离矩阵,并从波像差理论出发,寻求出调整误差作用分量的分立表现形式及影响参数,建立了计算机辅助检测大口径光学离轴非球面反射镜的基本模型。仿真分析结果证实了这种方法的可行性。     

非球面零位补偿检测中非线性误差的影响及去除

非球面零位补偿检测中会引入非线性误差,利用光线追迹的方法获得了干涉测量坐标系和非球面镜面坐标系之间的非线性关系。对某有效通光口径为860mm的体育场形离轴非球面反射镜的零位补偿检测,利用光线追迹结果进行坐标反变换的数据处理方法,对上述非球镜面面形数据进行了镜面矢高分布数据的非线性校正;通过分析对比非线性校正前后的数据,对计算机辅助装调过程的影响,证明经过非线性校正后的镜面面形矢高数据可以加速计算机辅助装调过程收敛。     

高精密光学元件磨床的加工与检测系统的开发

高精密平面磨床是加工光学非球面元件的一种重要途径.出于通用性和效率的考虑,开发一套面向光学非球面元件的高精密平面磨床的加工与检测系统,以此来实现光学非球面元件的精密加工.以自行开发研制的四轴数控高精密平面磨床为研究基础,采用模块化设计,选用Delphi 7为开发语言,运用Delphi 7和Matlab混合编程技术,搭建了加工与测量系统,实现了光学非球面元件的磨削加工、面形测量、磨削补偿以及环境检测等.实验结果表明,该系统可以满足光学元件的精密加工及检测,并具有较高的工作效率.     

用干涉条纹密度确定非球面检测点光源的最佳位置

在对非球面的干涉检测中,记录干涉图的CCD的选型、光路中光学器件的选择和干涉图的分析计算以及检测系统的精度评价等,都与干涉入射点光源和参考点光源的位置直接相关。为了能够准确地预判非球面检测时入射球面光波和参考球面光波的点光源最佳位置,采用计算和分析在点光源与被测非球面反射光波的干涉条纹密度的方法,确定非球面干涉检测时入射球面光波和参考球面光波的点光源的最佳位置。通过上述方法不仅能够确定非球面检测时点光源的最佳位置,还可用于全面地分析干涉条纹密度的分布,并用于制定检测系统CCD等光路元件选型的基本策略,也可用于对非球面检测的调试过程进行理论指导。     

小型非球面超精密加工建模及控制技术研究

根据高精度小型非球面制造的需要,探讨了一种针对小型非球面元件的加工方法,并分析了实现数控加工控制的技术途径.根据非球面加工理论,基于工控机和Windows系统,用VB.NET开发实现了小型非球面数控加工控制软件.     

实现长焦深的衍射光学元件设计方法

提出了一种设计长焦深小焦斑衍射光学元件的方法.该方法采用ZEMAX光学设计程序,利用能量守恒原理求解目标函数,并综合考虑焦斑大小保持不变的要求,对目标函数进行了修正,通过修正后的函数来约束输出光束在焦深范围内的轴上位置,从而完成衍射光学元件的相位优化,并求得相应的工艺参数.该元件不但可以使激光束具有长焦深和小焦斑,而且还具有可加工性.焦深范围能达到2 mm,焦深范围内光斑半径在5.32～10.48μm变化,与相同参数的传统光学元件相比,焦深增加了8倍,焦斑半径变化很小,而普通光学元件在此范围内最大焦斑半径达到102.9μm.该方法为长焦深元件的设计、加工与制造提供了可行方案.     

磁流变抛光光学非球面元件表面误差的评价

正确评价抛光后光学非球面元件表面面形的波前畸变是确保实现光学非球面元件超精密制造的关键。该文提出了结合功率谱密度法和残余误差法并考虑非球面元件表面中频误差的综合评价方法。将提出的综合评价标准应用到磁流变数控抛光过程中,进一步明确了表面残余误差与抛光工艺参数之间的关系,建立了有效消除表面残余误差的抛光工艺规范。按照这一工艺规范制造出一块抛物面光学反射镜,其面形精度达到λ/30(λ=0.6328μm),残余误差为3λ/1000。该方法可为深入开展高精度磁流变抛光技术研究提供参考。     

数控车床中刀具补偿的研究

在数控加工中,工件坐标系确定后,还要确定刀尖点在工件坐标系中的位置,即常说的对刀问题。车刀刀尖半径补偿是数控车削加工中的常见问题,本文就刀尖半径的影响进行分析,根据不同功能的数控系统进行刀尖半径补偿方法等进行介绍。     

数控车床中刀具补偿的研究

在数控加工中,工件坐标系确定后,还要确定刀尖点在工件坐标系中的位置,即常说的对刀问题。车刀刀尖半径补偿是数控车削加工中的常见问题,本文就刀尖半径的影响进行分析,根据不同功能的数控系统进行刀尖半径补偿方法等进行介绍。     

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.     

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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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