旋风铣削运动的矢量建模

旋风铣削法是一种较先进的高效率加工螺纹方法,适用于批量较大的螺纹粗加工,通过矢量分析,建立了旋风铣削运动的矢量模型,并在此基础上得出了描述旋风铣削运动的矢量表达式。     

精密镗削头动态性能研究

本文通过对某厂国产与进口的同类型精密镗削头动态性能测试分析．查明了这两种精密镗削头的主要差异、为国产精密镗削头的性能改进提供了可靠的依据。     

精密镗削头振动模态的实验研究

通过对国产与进Ｄ的同类型精密镗削头振动模态实验研究，找出了这两种精密镗削头的固有振动频率，给出了它们的各阶动画振型图．从这一侧面解释了国产精密镗削头回转精度偏低的原因。     

梯形螺纹丝杆的旋风铣削工艺及铣刀的精确设计

本文介绍了梯形螺纹丝杆的旋风铣削工艺,并对旋风铣刀刃形精确设计进行了公式推导和实例计算。     

实现立式加工中心成形法铣削硬齿面准双曲面齿轮大轮

提出了基于立式加工中心用指形铣刀成形法高速铣削硬齿面准双曲面齿轮大轮的加工方法。通过设计附加的铣齿装置,结合适合高速铣削的工艺参数,编制相应的数控加工程序,在立式加工中心上使用指形铣刀进行大轮的半精加工和热后精加工,并对其进行滚动检验。结果表明:这种加工方法有效地降低了螺旋锥齿轮的加工成本,提高了齿面的加工质量,实现了以铣代磨。     

基于AI控制中数控高速高精加工应用研究

数控技术的典型应用是:单机,复合,FMC/FMS/CIMS其发展方向是高速度化、高精度化、高效加工、智能化等,其中高速高精加工于80年代进入了一个高速发展时期,90年代在制造业广泛应用。本文阐述了基于AI控制的先进金属切削加工技术,由于它大大提高了切削率和加工质量,又称为高性能加工。结合加工实践,介绍了几种常用的切削指令及应用,多用于铣削加工。     

面向钛合金结构件的铣削刀具性能评价

航空钛合金结构件具有材料和结构双重难加工特性,选择刀具时既要考虑刀具/工件在材料方面的匹配,又要关注刀具/工件在结构方面的匹配.针对目前国内航空制造业在钛合金结构件高性能加工方面对铣削刀具选择及评价的迫切需求,在已有研究的基础上设计了综合考虑航空钛合金结构件难加工特征的典型基准件模型,基于模糊数学理论分别构建了粗、精加工刀具性能模糊综合评价模型,并进行了基准件模型铣削试验,应用所构建的综合评价模型对铣削刀具性能进行综合评价与分析.研究结果表明,所构建的基准件模型和模糊综合评价模型可以准确、快捷地评价铣削刀具性能.     

大中直径螺旋焊管切管机的试验研究

介绍一种采用机械式铣削方法(旋风铣)来切断螺旋焊管的移动式切管机,并在实验的基础上与其它方式的切管方法进行了分析对比,从而肯定了这种切管方式的较大的优越性.     

50%SiCp/Al复合材料的电弧铣削与铣磨组合加工

为了解决传统方法在高体积分数SiCp/Al复合材料加工中效率不高、易产生表面缺陷的问题,提出了一种电弧铣削与铣磨组合的高效精密加工方法.实验结果显示,采用电弧铣削进行50%SiCp/Al复合材料的粗加工,材料去除率可达6 300mm~3/min,再铸层厚度可控制在100μm以内,对后续精加工不会产生不良影响;采用铣磨进行50%SiCp/Al复合材料的精密加工,可避免产生崩边等表面缺陷,表面粗糙度(Ra)可达0.8μm.针对红外位标器支架的产品加工实验,验证了该组合加工方法的高效性与可靠性.     

螺纹硬态旋风铣削轴承钢GCr15切屑形貌及特性试验研究

为了揭示螺纹硬态旋风铣削的材料去除和切屑微观锯齿成形机理,采用金相显微镜、扫描电镜(SEM)和纳米压痕法硬度测试等对淬硬轴承钢GCr15的旋风铣削切屑的锯齿形貌几何特征、显微结构和纳米硬度进行试验研究,观测并分析其在切屑上的分布及变化规律,并讨论锯齿节在切削力、热作用下的形成机理。研究结果表明:旋风铣削切屑微观锯齿高度、齿距、锯齿化程度、倾斜角和变形系数在长度方向上存在波动;显微结构和纳米硬度在宏观切屑长度上和微观锯齿上分布不均匀;绝热剪切带和第二变形区的材料经历了剧烈的剪切变形和二次淬火,其硬度高于内部基体和未加工工件表面的硬度。这解释了锯齿特征波动的原因,说明单次切削过程中力、热条件的不稳定性。     

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