热处理对Fe83Ga17合金磁致伸缩和有序-无序的影响

实验研究了热处理对〈110〉取向多晶Fe83Ga17合金磁致伸缩性能和有序-无序度的影响.发现冷却速度的不同直接影响着合金的有序程度和磁致伸缩性能,部分有序的Fe83Ga17合金样品磁致伸缩性能最好,水中淬火处理后,在20 MPa预压力作用下,Fe83Ga17饱和磁致伸缩系数λs达到298×106.     

第三组元(Al、Cu)添加对Fe_(83)Ga_(17)合金相结构和磁致伸缩性能的影响

通过非平衡凝固方式制备Fe83Ga17-xMx(x=0、1、2、3;M=Al、Cu)合金,并对合金的相组成及其磁致伸缩性能进行研究.结果表明:合金保持A2(bcc-Fe(Ga))相结构,Al、Cu均固溶于Fe-Ga合金,添加的Al优先存在于Ga-Ga团簇当中,并与Fe形成bcc结构的Fe-Al固溶体;随着添加量的增大,Cu从基体中析出,并在晶界处富集.Al和Cu均对Fe83Ga17合金磁致伸缩性能产生抑制作用,Cu的抑制作用要小于Al.对于Fe83Ga17-xAlx合金,当x=2时,饱和磁致伸缩值达到最大;添加Cu的试样中,当x=2、3时,饱和磁致伸缩值均达到最大.     

热处理对深过冷快速定向凝固Fe-Ga合金组织和性能的影响

Fe-Ga合金后续的热处理工艺同合金的成分配比、制备工艺一样,对合金的磁致伸缩性能有重要影响.采用熔融玻璃净化与循环过热相结合的方法,制备深过冷快速定向凝固〈110〉轴向取向的Fe83Ga17合金棒材,分别采用高温和低温淬火工艺,研究淬火前后合金的组织和磁致伸缩性能.结果表明:快速定向凝固Fe83Ga17合金从不同温度淬火至室温,合金在TC附近淬火获得较高的磁致伸缩应变,淬火可抑制有序DO3相的形成,与高温淬火工艺相比,在TC附近淬火,只有部分特定区域优先得到淬火,发生modified-DO3相转变,并部分保留高温无序组织,最终获得有序-无序的室温组织,这种组织有利于Fe-Ga合金磁致伸缩性能的提高.     

硼和铬对多晶Fe83Ga17合金磁致伸缩和室温力学性能的影响

研究了添加B和Cr对多晶Fe83Ga17合金磁致伸缩和拉伸力学性能的影响. 结果表明:在Fe83Ga17合金中添加原子分数1%的B,不仅提高了合金的磁致伸缩性能,而且还大幅提高了合金的室温力学性能,抗拉强度达到548 MPa,延伸率达到3.56%. B元素以Fe2B相的形式偏聚在晶界,细化了合金晶粒,增加了合金晶界结合力,抑制了沿晶脆断. 添加原子分数2%的Cr,Cr固溶在Fe83Ga17合金中,同时提高了合金的磁致伸缩性能和室温力学性能,(Fe83Ga17)98Cr2合金最大磁致伸缩系数达到7×10-5,延伸率也较Fe83Ga17合金有所增加,达到0.6%.     

Tb_(0．3)Dy_(0．7)(Fe_(0．9)T_(0．1))_(1．95)合金的结构磁性能、磁致伸缩和自旋重取向温度研究

本文系统研究了室温下Tb_(0.3)Dy_(0.7)(Fe_(0.9)T_(0.1))_(1.95)(T=Mn,Fe,Co,B,Al,Ga)合金中ⅢA族金属和过渡金属T替代Fe对晶体结构、磁性能、磁致伸缩和自旋重取向温度的影响。结果发现,不同金属T替代Fe,Tb_(0.3)Dy_(0.7)(Fe_(0.9)T_(0.1))_(1.95)合金具有相同的MgCu_2型立方Laves相结构。除Co之外,其它金属替代均使合金的点阵常数有不同程度的增大,而Curie温度有所降低。T替代Fe使合金的比饱和磁化强度增大。ⅢA族金属B,Al,Ga替代使磁致伸缩λ_s下降幅度较大,而且Al,Ga替代使磁致伸缩容易饱和,表明Al,Ga替代可降低合金的磁晶各向异性,而过渡金属Mn,Co替代Fe使合金磁致伸缩λ_1下降幅度较小,不同替代金属元素,对内禀磁致伸缩λ_(111)有不同的影响。同时还发现,替代使合金的自旋重取向温度略有下降。     

定向凝固Fe83Ga15Al2合金的结构及磁致伸缩性能

系统研究不同定向凝固速率下Fe83Ga15Al2合金的相组成和磁致伸缩性能.结果表明,经过区熔定向凝固后,Fe83Ga15Al2合金的晶粒尺寸与铸态相比要大得多.当凝固速率较高时,晶粒没有明显的取向性,而当速率较低时,显示出沿轴向的取向性,同时也存在很多横向亚晶界.铸态的Fe83Ga15Al2合金在经过区熔定向凝固之后,磁性能有大幅度提高,低场响应快,且磁致伸缩值增大,凝固速率v=10μm/s时,磁致伸缩系数达到最大值53×10-6;当v=300μm/s时,λ值略低,为50×10-6,但其低场响应迅速,在50kA/m时就达到最大值.     

Tb_(0.3)Dy_(0.7)(Fe_(0.9)T_(0.1))_(1.95)合金的结构、磁致伸缩和Mssbauer研究

系统研究了室温下Tb0.3Dy0.7(Fe0.9T0.1)1.95(T=Mn,Fe,Co,B,Al,Ga)合金中ⅢA族金属和过渡金属元素T替代Fe对晶体结构、磁致伸缩、内禀磁致伸缩、自旋重取向的影响.结果发现,不同金属T替代Fe,Tb0.3Dy0.7(Fe0.9T0.1)1.95合金具有相同的MgCu2型立方Laves相结构.ⅢA族金属B,Al,Ga替代使磁致伸缩λs下降幅度较大,同时发现Al,Ga替代使磁致伸缩容易饱和,表明Al,Ga替代可降低Tb0.3Dy0.7(Fe1?xTx)1.95合金的磁晶各向异性,而过渡金属Mn,Co替代Fe使Tb0.3Dy0.7(Fe1?xTx)1.95合金磁致伸缩λs下降幅度较小;不同替代金属元素,对内禀磁致伸缩λ111有不同的影响.M?ssbauer效应表明,Al,Ga替代使Tb0.3Dy0.7-(Fe0.9T0.1)1.95合金的易磁化方向在{110}面逐渐偏离了立方晶体的主对称轴,即自旋重取向,B,Mn,Co替代未使易磁化轴发生明显转动.     

Tb0.3Dy0.7(Fe0.9T0.1)1.95合金的结构、磁致伸缩和M(o)ssbauer研究

系统研究了室温下Tb0.3Dy0.7(Fe0.9T0.1)1.95 (T = Mn, Fe, Co, B, Al, Ga)合金中ⅢA族金属和过渡金属元素T替代Fe对晶体结构、磁致伸缩、内禀磁致伸缩、自旋重取向的影响. 结果发现, 不同金属T替代Fe, Tb0.3Dy0.7(Fe0.9T0.1)1.95合金具有相同的MgCu2型立方Laves相结构. ⅢA族金属B, Al, Ga替代使磁致伸缩(s下降幅度较大, 同时发现Al, Ga替代使磁致伸缩容易饱和, 表明Al, Ga替代可降低 Tb0.3Dy0.7(Fe1-xTx)1.95合金的磁晶各向异性, 而过渡金属Mn, Co替代Fe使Tb0.3Dy0.7(Fe1-xTx)1.95合金磁致伸缩λs 下降幅度较小; 不同替代金属元素, 对内禀磁致伸缩(111有不同的影响. M(o)ssbauer 效应表明, Al, Ga 替代使 Tb0.3Dy0.7- (Fe0.9T0.1)1.95合金的易磁化方向在{110}面逐渐偏离了立方晶体的主对称轴, 即自旋重取向, B, Mn, Co替代未使易磁化轴发生明显转动.     

快淬速度对Fe_(83)Ga_(17)Ce_(0.8)合金微结构和磁致伸缩性能的影响

采用熔炼法和快淬法分别制备了铸态和快淬态Fe83Ga17Ce0.8合金,研究了快淬速度对铸态和快淬态Fe83Ga17Ce0.8合金的组织结构和磁致伸缩性能的影响.结果表明,所有合金的基体为Fe(Ga)无序固溶体相,铸态和6m/s快淬态Fe83Ga17Ce0.8合金中均含有小量的CeFe2相,快淬导致微量非对称结构的DO3相析出.随着快淬速度的增大,合金的磁致伸缩系数绝对值先增大后大幅度减小.6m/s快淬态合金的磁致伸缩系数最大,在外磁场为557kA/m时达到382×10-6.6m/s快淬态合金大的磁致伸缩性能主要来源于合金中形成的CeFe2相和析出的非对称结构的DO3相.     

取向多晶Fe-Ga合金结构与磁致伸缩应变研究

采用定向凝固的方法实验研究了取向多晶Fe-Ga合金的磁致伸缩性能.发现〈110〉轴向取向的Fe-Ga合金具有较大的磁致伸缩应变.在零预压力下,其饱和磁致伸缩应变λs为188×10-6;在20 MPa预压力下,λs可以达到286×10,具有明显的压力效应.还观察到在大的预压力(＞15 MPa)作用下,在低磁场范围出现负磁致伸缩应变现象.     

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     

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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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has