机械合金化制备Mg58Cu42非晶态合金粉末的机理研究

采用X射线衍射和扫描电子显微镜,研究了Mg58Cu42混合粉末在机械合金化过程中的结构和微观形貌变化.结果表明,Mg,Cu粉末在机械合金化过程中是互溶的,机械合金化可以大大提高它们之间的固溶度.球磨过程中,Mg原子逐步溶入Cu基体中,同时,发生晶粒的细化和非晶化过程,并且随着球磨时间的延长,粉末逐渐细化.然后,形成Mg在Cu中的过饱和固溶体;固溶体的变形能量积聚到很大时,发生固溶体晶体结构失稳,最后形成Mg和Cu分布均匀的非晶态合金粉末.     

机械合金化强度对Fe—Ni—P—B系合金非晶形成的影响

本文用机械合金化法研究制备Fe-Ni-P-B系非晶材料,用X射线衍射仪和透射电子显微镜对经不同球磨工艺处理的Fe40Ni40P14B6及Fe61.6Ni15.4Cu1Nb2P14B6两种成分的粉末进行了分析,得出结论：成分为Fe61.6Ni15.4Cu1Nb2P14B6的粉末,在一定的球磨强度下,可通过机械合金化获得非晶。     

Fe3P化合物的机械合金化制备与结构研究

采用机械合金化法和固态反应法制备了Fe3P化合物,用X-射线衍射确定样品的晶体结构,结果表明,随着球磨时间的增加,Fe、P混合粉末的颗粒度逐渐减小,当球磨时间增加到100h时,衍射峰基本消失,混合物呈现非晶态.在1273K下退火70h后.混合粉末样品形成单一的Ni3P型四角结构,空间群为1-4.     

球磨工艺参数对Y2O3和Al2O3混合粉末机械合金化的影响

研究了在机械合金化Y2O3和Al2O3混合粉末的过程中,球磨工艺(球料比、转速、球磨时间)对机械合金化过程的影响。实验结果表明,采用球料比为20∶1,转速为500 r/min,能够获得较高的球磨能量,经10 h机械合金化即可促使Y2O3和Al2O3粉体发生固相反应,合成YAlO3(YAP)。     

球磨时间对Cu/MgCu_2复合材料组织与性能的影响

采用机械合金化+热压烧结制备Cu/MgCu2复合材料.研究Mg-83.7Cu配比成分的Mg、Cu元素粉末经不同球磨时间后的物相和颗粒尺寸的变化,以及在650℃,1h热压工艺下所获得的Cu/MgCu2复合材料的组织与性能.结果表明:随着球磨时间的增加,Mg、Cu粉末的衍射峰不断宽化,粉末颗粒经历一个由粗到细的转变过程,且在前20h变化明显;且随着粉末球磨时间的增加,Cu/MgCu2复合材料的组织分布均匀,晶粒尺寸细化,致密度高,复合材料的维氏硬度、抗压强度、抗弯强度及断裂韧性也均增加,但球磨时间超过20h后增加缓慢.     

Al1-xFex混合粉末的机械合金化

对Al1-Fe(x-5，50，75at％)混合粉末进行了球磨，用X射线、电镜等分别研究了球磨粉末的结构和形貌．得到了Al95Fe5中AI相的有效晶粒尺寸和Alt-xFex的平均晶粒尺寸随球磨时间的变化，其变化规律是先增大，再减小，最后达到稳定值而不再变化．得到了Al95Fe5中的晶格畸变，也出现交替变化．对于Al1-xFex混合粉末，Al，Fe成分越接近，机械合金化过程中扩散越易于进行．球磨样品晶粒尺寸越小，聚集的趋势越小．固溶体的溶解度与混合粉末的成分有关．     

固液反应球磨制备Al-Cu-Fe与Al-Si-Fe三元合金

利用固液反应球磨技术,采用Fe球球磨液态Al-Cu和A1-Si三元合金,研究了Al-Cu-Fe和Al-Si-Fe三元合金相形成规律.在923 K球磨液态的Al-33.2%Cu共晶合金,球磨48 h后,得到Al13Cu4Fe3的固相粉末;在943 K球磨Al-54%Cu(Al2Cu)合金熔体,球磨24 h后,Al2Cu的液相消失,得到了固相的Al65Cu20Fe15和Al13Cu4Fe3混合粉末;在963 K球磨Al-7%Si亚共晶合金熔体,球磨48 h后,Al-Si液相消失,得到固态的Al8Fe2Si合金粉末;在963 K球磨Al-12.6%Si共晶合金熔体,球磨48 h后,Al-Si的液相消失,得到固态的Al8Fe2Si粉末;在1133 K球磨Al-30%Si过共晶合金熔体,球磨24 h后,Al-Si的液相消失,得到固态的Al3FeSi合金粉末.在上述球磨中,若加入一定量的Fe粉,将加速反应进程.固液反应球磨产物是在打击剥离的过程中制得的.     

固液反应球磨制备Al-Cu-Ni三元金属间化合物粉末

利用固液反应球磨技术制备了Al-Cu-Ni三元合金粉末.采用Ni球球磨wAl-33.2%wCu,wAl-54%wCu(Al2Cu)和wAl-70%wCu(AlCu)二元合金熔体,在893 K分别球磨wAl-33.2%wCu熔体12 h和24 h后均生成了Al7Cu4Ni粉末;在893 K球磨wAl-54%wCu12h后生成Al7Cu4Ni粉末,在993 K和1 123 K球磨wAl-54%wCu(Al2Cu)24 h后均生成Al0.28Cu0.69Ni0-粉末;在1 123 K球磨wAl-70%wCu(Al2Cu)24 h后生成Al0.28Cu0.69Ni0-粉末.同时,对Al-Cu-Ni三元合金相形成规律进行了研究,对固液反应球磨机理进行了探讨.     

钇对AlW系统机械合金化的影响

用机械合金化方法对成分为（Al0.9W0.1）1-xYx（x=0,0.05,0.1）和（Al0.8W0.2）1-xYx（x=0,0.1）混合粉末进行了不同时间的研磨,用X射线衍射对球磨后的粉末结构进行了分析,结果表明,合金化过程主要是Al和Y固溶剂到W中,钇的加入有利Al在W中的溶解,同时,钇能缩短合金化的时间,加速机械合金化的过程。     

Fe-Ni磁性材料机械合金化的成分及组织特征研究

用扫描电子显微镜、X射线能谱仪及X射线衍射仪考察分析了Fe和Ni混合粉末的机械合金化过程及其组织特征,得出结论Fe和Ni粉末的机构合金化是通过片层间的扩散进行的;球磨10h后,Fe和Ni粉末发生合金化;进一步球磨,已合金化的粉末又会发生相变。     

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

正~~