电阻焊接用高强Q125级石油套管钢组织及其性能

设计了一种低合金含量的Q125级高强度石油套管用钢,研究了热处理工艺对实验钢组织和力学性能的影响．与870℃淬火＋500℃回火工艺相比,实验钢在850℃淬火＋500℃回火工艺下具有更好的强韧性配合．与870℃淬火相比,850℃淬火处理的奥氏体晶粒尺寸较小,使决定钢力学性能的晶区、板条束尺寸细化,因此其性能更优异．淬火温度对实验钢的析出行为影响不大．尺寸较大的TiN以及TiC和TiN复合析出物对奥氏体晶界起到钉扎作用,可以抑制奥氏体晶粒的长大;含有Mo的尺寸较小的TiC可以起到钉扎位错的作用,阻止位错移动,对强度的提高贡献很大．     

9Cr—1Mo—V—Nb耐热钢焊接接头组织分析

文章分析了９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ与几种常用耐热钢焊接接头的显微组织,表明试验的各种焊接接头的机械性能良好．各焊接接头回火后焊缝区的显微组织均为回火马氏体,这与９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ钢正火回火态的显微组织相类似,但晶粒相对粗大．９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ同类钢焊接接头过热区显微组织为回火马氏体,局部地区有少量δ铁素体．９Ｃｒ－１Ｍｏ－Ｖ－Ｎｂ钢与合金元素较低的异类钢焊接接头过热区的晶粒长大程度较同类钢为甚,碳化物聚集长大较显著．     

SPV490钢板直接淬火回火工艺的研究

针对SPV490钢控轧后的直接淬火回火工艺进行研究.结果表明,采用再结晶区控轧后结合直接淬火回火工艺时,实验钢的强度大幅度提高,但韧性下降;采用在奥氏体再结晶区变形44%,然后在未再结晶区变形的两阶段控轧工艺后结合直接淬火回火工艺时,由于在细化晶粒的基础上增加晶粒内部变形带数量及位错密度,从而获得细小、均匀的组织,实验钢的综合力学性能良好.     

3Cr2W8v钢超细化的研究

通过快速加热循环淬火法对3 Cr 2 W8V钢进行了一系列相变超细化的试验,证明该钢经900～1100℃快速加热循环淬火2次以上即有明显细化晶粒的效果,可使其热轧退火态下的11级晶粒度细化到14级以上;其中通过1000℃快速加热2～3次可使晶粒度细化到15级以上.在快速加热循环淬火之前,增加一次1100～1160℃的固溶处理,还可使钢中的碳化物进一步得到细化.但固溶处理的温度接近或超过1200℃时,则会引起钢的晶粒显著粗化,而对随后的循环淬火组织产生遗传性.经过2次快速加热循环淬火,而后再经正常淬火回火后,钢的强度极限可有显著提高,而冲击韧性毫不降低.     

亚温淬火对35CrMo钢抗氢脆性能的影响

本试验结果表明：３５ＣｒＭｏ钢在亚温淬火温度高于７９０℃（即钢中残留的铁素体量低于１１．２％），并经高温回火后，它的抗拉强度、屈服强度以及常温冲击韧性都有明显的提高，钢的氢脆敏感性也得到改善．初步认为亚温淬火细化了晶粒和组织是各项性能获得改善的主要原因．     

55NiCrMoV7回火钢的组织定量分析

通过SEM、TEM、XRD、图像定量分析和维氏硬度测量。定量研究了55NiCrMoV7钢在100～700℃、90s-665h之间回火的组织和硬度变化．结果表明。钢中的原奥氏体晶粒、马氏体板条不因回火过程而改变。回火析出碳化物的体积分数在一定回火温度时间范围内保持恒定。但是碳化物的形态和尺寸随回火工艺而改变．     

铈在钢中的晶界偏聚行为与高温回火脆性

稀土元素在钢中细化奥氏体晶粒、提高钢的淬透性、减弱回火脆性、提高钢和合金的高温持久强度等方面的作用已有不断报导。但稀土元素在钢中的合金化作用还研究得不充分,稀土元素在晶界的偏聚,特别是在长时间回火时的晶界偏聚行为还很少研究。     

热处理条件对32CrNiMoV钢力学性能的影响

研究了热处理条件对32CrNiMoV高强钢力学性能的影响，实验结果表明，淬火温度为860－920℃，回火温度为550－660℃时，该钢的低温冲击韧性，断裂韧性和抗拉强度可获良好的匹配。     

淬火-回火工艺对X80管件钢组织性能的影响

采用扫描电子显微镜(SEM)、电子背散射衍射分析技术(EBSD)和透射电子显微镜(TEM)等实验手段,研究了不同淬火--回火热处理工艺制度对X80管件钢组织性能的影响.结果表明:一次930℃淬火后,随着回火温度的升高,实验钢屈服强度先升高后降低,在630℃达到最大值588MPa;抗拉强度随回火温度升高持续下降,680℃时降至630MPa.二次两相区淬火,经630℃回火后,X80管件钢有最佳的综合力学性能,-50℃冲击韧性显著提高,Ak达到210J.这是由于二次淬火温度在860℃两相区时,组织中奥氏体晶粒大幅细化,经630℃回火后,细晶马氏体组织中出现位错亚结构的回复软化、板条边界钝化和块状M-A组元分解产生的析出强化机制综合作用的结果.     

不同热处理工艺下H13钢组织性能的变化

文章通过热处理工艺参数的变化研究了H13钢组织结构及力学性能的变化规律.试验结果表明,H13钢经过1050℃淬火、600℃2次回火后获得良好的力学性能,伸长率达到7.55%左右,抗拉强度达到1340 MPa;淬火温度高于1080℃后,奥氏体晶粒明显长大,淬火冷却后晶粒不均匀;回火次数2次最佳.     

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