电磁场对铸轧板织构和力学性能的影响

采用三维取向分布函数（ＯＤＦ）研究了电磁场对铸轧板织构和力学性能的影响．结果表明，施加电磁场的铸轧带坯与通常添加铝－钛－硼变质剂的铸轧带坯间存在一定的织构差异．将上述７．４ｍｍ厚的带坯冷轧成１．０ｍｍ的成品板经３６０℃（１ｈ）退火处理后，电磁铸轧板较易获得立方织构与加工织构的组合，其深拉性能明显优于通常添加铝－钛－硼丝的铸轧板．此外，还讨论了铸轧板织构的形成机理．     

用ODF图的诠释图分析铸轧3004铝合金板织构

本文采用了自编制的立方系取向分布函数（ＯＤＦ）图的诠释程序，提供了恒的ＯＤＦ图的诠释图，并且用该诠释图成功地分析了铸轧３Ｏ０４铝合金板织构状态．     

深冲用冷轧薄钼板晶体空间取向分布的研究

本文利用晶体取向分布函教研究了国产冷轧钼板的直轧和交叉轧制织构。结果表明,直轧钼板的基本织构组分为:{001}〈110〉织构、轧向〈011〉纤维织构和轧面{111}纤维织构;交叉轧制使钼板中{001}〈110〉织构和{111}纤维织构同时明显增加。通过对晶体取向分布特征的全面分析,初步探讨了轧制过程中晶粒转动的规律,为提高钼板深冲性能提供了一定的依据。     

退火工艺对AZ31B镁合金铸轧板组织和性能的影响

研究不同退火温度、时间对普通铸轧和复合能场(电磁场+超声波)铸轧AZ31B镁板组织及性能的影响。研究结果表明:铸轧镁板的再结晶温度在复合能场作用下降低了约50℃;250℃退火时,普通铸轧镁板无明显再结晶,复合能场铸轧镁板局部再结晶;在300℃,4 h时,铸轧镁板均充分再结晶,复合能场铸轧镁板晶粒细小,组织均匀,平均晶粒直径为8~13μm,而普通铸轧镁板晶粒平均晶粒直径为14~19μm;400℃退火时,晶粒开始粗大,1 h时复合能场铸轧镁板与普通铸轧镁板的平均晶粒直径分别为28~33μm和20~25μm。退火后,铸轧镁板内析出相数减少,复合能场铸轧镁板析出相弥散分布在晶界上,普通铸轧镁板析出相较多并富集在晶界和晶界附近。退火后铸轧镁板的塑性变形能力明显改善,在300℃,4 h时,复合能场铸轧镁板的硬度、抗拉强度、屈服强度、伸长率比普通铸轧镁板分别提高了4.7%,17.2%,34.1%和74.6%。     

铝带坯铸轧板形测控的补偿模型

根据铸轧板形缺陷的表征特点及其评价指标 ,采用铸轧板带的横向板厚分布作为板形控制信号 ,并依此建立了铸轧板形的数学描述 .基于铸轧工艺的特点 ,在铸轧板形实测信号中通常包含铸轧带材横向温差及板凸度所致的两种附加干扰 ,通过具体分析两种附加干扰对铸轧板形测控的影响 ,分别建立了附加温差板形补偿模型和附加板凸度板形补偿模型 .针对某铸轧机实轧工况 ,运用所建补偿模型求得了横向板厚的补偿值 ,并直接对板形检测信号进行修正 ,以期提高板形控制精度 ,避免板控执行机构的误操作 .实测结果表明所建补偿模型正确 ,且处理方法简单 ,可直接用于铸轧板形的控制 .图 1,表 1,参 10     

双辊铸轧薄带钢侧封板磨损机理及热应力分析

为了提高双辊铸轧薄带钢工艺中侧封板的使用寿命,设计了单独式和组合式的侧封板并对制作侧封板的材料进行了评价·采用抗钢水侵蚀浸蘸实验和铸轧实验,观察了侧封板的腐蚀、磨损和裂纹分布规律·利用ANSYS有限元分析软件对侧封板的温度场和热应力场进行了数值模拟,比较了不同预热温度条件下的热应力分布规律·结果表明,组合式侧封板对铸轧过程的稳定性和改善侧封板的使用寿命效果较好,氧化锆质耐火材料制作的侧封板具有较好的综合性能,熔融石英侧封板的腐蚀主要是由于SiO2与钢水中的MnO反应生成低熔点的化合物所致,侧封板的裂纹和损坏主要是由于应力分布不均的结果     

双辊铸轧镁合金板表面形貌及微观组织分析

以自行设计的立式双辊铸轧机铸轧出的厚度为2.5～5.0mm的镁合金铸板为研究对象,提取镁合金板铸轧过程中铸轧速度、铸轧力及辊缝实时变化数值,分析了铸板板形的波动原因,观察了不同铸轧速度条件下镁合金板的表面形貌和微观组织。当铸轧速从8m/min提高到16m/min时,铸板厚度由5.0mm减小到2.5mm,随着铸轧速度的提高,枝晶区比例相应提高。铸轧速度达到16m/min时,中心等轴晶区会缩小甚至消失。在本文实验冷却条件下,不同铸轧速度的铸板每侧枝晶生长高度距铸板表面都约为1mm,结果表明,2.5mm左右是铸轧较理想的板厚。     

电磁/超声能场对1060铝合金铸轧板组织性能的影响

在电磁和超声能场下铸轧出1060铝合金热带坯,并对其进行冷轧和退火实验,研究退火温度对复合能场铸轧板微观组织和力学性能的影响,并与相同条件下未施加电磁/超声外场的铸轧样品进行对比。研究结果表明:随着退火温度的增加,2种铸轧板的加工组织逐渐消失,再结晶组织不断增多,晶粒尺寸由小变大,其中复合能场铸轧板具有更低的再结晶开始温度,比未施加电磁/超声外场的铸轧板低50℃左右;复合能场铸轧板在各退火温度下的抗拉强度σb和伸长率δ均高于相同条件下的未施加电磁/超声外场样品,各向异性指数(IPA)明显小于未施加外场的铸轧板;随着退火温度的增加,2种铸轧铝板的制耳率出现先下降后增大的变化趋势,其中复合能场铸轧板经325℃退火后,出现沿0°,45°和90°方向的制耳,制耳率仅为1.7%,而未施加电磁/超声外场铸轧板出现45°方向的制耳,制耳率为3.7%。     

双辊铸轧奥氏体不锈薄带显微组织分析

对在异径双辊铸轧机上进行铸轧实验所得不锈钢薄带进行了显微组织分析·结果表明,铸轧不锈钢薄带的组织与常规铸造相比有很大不同,晶粒组织得到显著细化,组织形态和分布均有异于常规铸造组织·但是从其组织分布特征及奥氏体和铁素体的质量分数来看,铸轧薄带的组织与焊缝中的铸态组织相比有极大的相似性,这是由于其熔池的热力学特点的相似性决定的,因而可以用分析焊缝中组织特征的一些方法来分析铸轧薄带的组织特征     

冷轧压下率对双辊铸轧硅钢形变和再结晶织构的影响

2.0 mm厚双辊铸轧Fe-2.8%Si-0.8%Al硅钢带坯进行直接冷轧和退火,研究了不同冷轧压下率样品的形变与再结晶织构特征.形变织构主要由α(110//RD),γ(111//ND)和λ(001//ND)纤维织构组分构成,其取向密度峰值分别位于{001}110,{111}110和{001}110~210.随压下率提高(40%~90%),各主要形变织构组分增强,压下率为60%时,剪切带特征最显著.再结晶织构包含Goss({110}001),Cube({001}100),λ,{113}361和{111}112等织构组分.随压下率提高,再结晶机制由剪切带形核主导转变为形变带和晶界形核主导,导致再结晶Goss组分减弱,而{113}361,Cube,λ以及{111}112再结晶织构组分增强.     

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     

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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