Ni60喷熔层的切削加工

针对Ｎｉ６０喷熔层组织结构、切削加工特点、刀具材料的分析和研究，结合切削加工的理论和实践，给出了ＹＤ０５牌车刀切削加工的工艺参数：切削速度１０～２０ｍ／ｍｉｎ，切削深度０．０５～０．３０ｍｍ，刀具的前角为－５°～－１０°，后角为８°～１２°。同时，对高硬度Ｎｉ基喷熔层的切削加工提出了可参考的技术数据。     

振动参数对金刚石切削不锈钢零件影响规律研究

为减轻金刚石刀具的磨损,提高工件表面加工质量,采用超声振动的方法切削不锈钢零件．研究了不同振动参数对工件表面粗糙度和刀具磨损量的影响规律．对刀具的振动频率和振幅的影响进行了理论分析．在精密车床上进行了金刚石刀具超声振动切削不锈钢零件的加工实验．结果表明：振动参数对工件表面粗糙度和刀具寿命有较大的影响．在一定条件下,振幅越小,加工表面粗糙度越大,刀具磨损越快;振动频率越高,加工表面粗糙度越小,工具磨损越轻．     

非弹性散射和总截面的反常质量维度(S=10-100GeV)(英文)

在紫外不动点处,反常质量维度的实验值γｍ（ｇ※Ｒ）＝０．０７７２（Ｓ＝１０ＧｅＶ—１．８ＴｅＶ）,γｍ（ｇＲ）＝０．０５１７＋０．０００２（Ｓ＝２－１００ＴｅＶ,质子空气核）表明,电强相互作用的关系（ｇ※Ｒ～ｅ※Ｒ）普遍存在,且在ｇ※Ｒ＝０．３４８２３２（ＱＣＤ）,（ｅ※Ｒ）２／ｈｃ＝１／１２６．３０４９６２．     

内外螺旋三角翅片管管外冷凝传热建模与优化(Ⅱ)--数值分析与优化

为优化ＩＯＳＦ管的管外几何参数,根据所建数学物理模型,对不同换热工况和不同结构参数进行数值分析与模拟优化．研究结果表明：当管长Ｌ＝０．７ｍ、螺旋角β＝１８°、管外径Ｄｏ＝０．０１６ｍ,Ｈ＝０．００１ｍ时,φ＝７６°与Ｎ＝３２是最佳匹配参数,此时有最大平均冷凝换热系数;ＩＯＳＦ管管外螺旋角在β＜２７°的范围内,其管外传热特性与纵槽管基本相当;翅片夹角φ和螺旋槽头数Ｎ是对ＩＯＳＦ管管外冷凝换热产生主要影响的结构参数;局部冷凝换热系数沿管长跌落主要集中在开始的０．５ｍ内,因此排液盘的间距应不大于０．５ｍ,才能更有助于平均冷凝换热系数的提高     

等离子弧粉末堆焊最佳工艺参数的研究

通过正交设计确定等离子弧粉末堆焊工艺参数对堆焊层质量的影响,经过正交多项式回归分析得到Ｆｅ－０７合金粉末在Ｘ６５板材上表面堆焊的最佳工艺参数为Ｉ＝ １８０～１９０ Ａ,Ｇ＝ ４１．５ ｇ／ｍ ｉｎ,Ｖ＝ １０２ ｍ ｍ ／ｍ ｉｎ,Ｔ０ ＝ ３５０ ℃,Ｑ１ ＝ ２８０ Ｌ／ｈ,Ｑｓ＝ ４００ Ｌ／ｈ,并通过裂纹试验得出抗裂预热温度为３５０ ℃     

高能粒子碰撞中强子质量的产生(s=4～1800GeV)

近阈实验指出π＋π－介子在ｘμ＜２／３Ｍπ的球内产生，入射质量与新生质量的差别在Ｎπ±≥３时消失。本文研究了固定多重数Ｎ的能量—质量求和规则与强子质量的约束条件，得出在ｓ＝４～１８００ＧｅＶ范围内强子平均质量服从重正化群方程：〈ｍｃｈ〉＝ｍπ±ｅｘｐ［（０．０５１±０．００４）／αｓ］，强子的质量反常维度在固定点处为γｍ（ｇ∞Ｒ）＝０．０８０８，且对所有粒子是普适的     

车削不锈钢时切削条件对积屑瘤和切削温度的影响

本文采用快速落刀法、同时辅以测温试验以获得在自由直角切削情况下的若干切屑根部并做成显微金相磨片。用金属显微镜或从金相磨片的照片上测出积屑瘤的高度、底面长度和积屑瘤前角等参数从而定量分析了车削不锈钢时,切削速度、切削厚度和刀具前角对积屑瘤、切削温度的影响。本文根据实验结果指出了用W18Cr4V高速钢刀具加工1Cr18Ni9Ti不锈钢时,形成积屑瘤的速度范围为V=2～27米/分(当a_c=0.067～0.17mm时)。同时还测出对应于积屑瘤消失时的切削温度为500～520℃,而对应于积屑瘤高度达最大值时的切削温度为300℃左右。并指出加工奥氏体不锈钢时,当刀具前角γ_o>30°时不形成积屑瘤。本实验利用自然热电偶法配合光线示波器动态记录了各种切削条件下切削温度的变化。并用回归分析法整理出用高速钢刀具自由干切削1Cr18NiSTi钢时计算切削温度的指数公式。     

车削ZL109铝合金PCD刀具的 几何参数优化仿真

ZL109铝合金对刀具的磨损严重,难以获得较好的加工精度.而刀具几何参数对切削力、切削温度、表面加工质量和刀具耐用度都有重要的影响,对刀具几何参数进行优化具有重要意义.利用材料试验机和SHPB装置对ZL109进行准静态和动态冲击压缩实验,确定ZL109铝合金的本构模型参数.采用单因素试验法,模拟刀具的前角、后角和刀尖圆弧半径对切削力和刀尖温度影响.结果表明:刀尖圆弧半径对X和Y方向切削力的影响最大,前角对Z方向切削力的影响最大,而后角对刀尖温度的影响最大.通过正交试验法和极差分析,当刀具几何参数选择为前角γ0=0°,后角α0=7°,刀尖圆弧半径r=0.4 mm时,PCD车刀切削ZL109铝合金时刀具的切削性能最优.     

中密度纤维板切削力的研究

用二次回归正交组合设计法安排试验，采用二次回归数学模型分别拟合单位宽度的切削力Ｆｘ法向力Ｆ与刀具磨损ｂ，刀具前角γ及切削厚度ａ之间的关系，试验分析表明Ｆｘ用二次回归曲线方程在水平ａ＝０．００１下显著，Ｆｙ的二次回归曲线方程在水平ａ＝０．１下不显著。     

“欧拉型”公式（式7）的极限

“欧拉型”公式（式７）的极限１Ｋｎ的极限取当ｎ→∞时，Ｋｎ的极限．由包角α＝２（ｎ－１）γ，则ｎ＝α２γ＋１，因α为定值，当ｎ→∞时，γ→０．Ｋｎ的极限为ｌｉｍｎ→∞Ｋｎ＝ｌｉｍｎ→∞ｃｏｓγ＋ｆｖｓｉｎγｃｏｓγ－ｆｖｓｉｎγｎ＝ｌｉｍγ→０ｃｏｓ...     

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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