巨磁电阻锰氧化物材料的低温电阻率行为的研究

对巨磁电阻锰氧化物材料(1-x)La2/3Ca1/3MnO3/(x)YSZ(钇稳定氧化锆)—(1-x)LCMO/(x)YSZ系列样品低温下电阻率行为进行了研究.(1-x)LCMO/(x)YSZ的R-T曲线低温拟合系数的分析结果表明,在低温下电阻率行为式ρ=0ρ ATa BTb中,b=5是合理的,T5代表电子-声子散射项.     

三元混晶AxB1—xC中极化子回旋质量

研究了三元混晶A_xB_(1-x)C中弱耦合磁性极化子问题,用微扰理论导出了极化子朗道(Landau)能级和回旋质量与外磁场B和混晶组分x的关系,并对结果进行了数值计算,与其它理论结果进行对比。当组分x=0(或1)时,得出的结果与相应的二元晶体BC(AC)的结果完全等价。     

基于同步辐射的X射线吸收谱探讨LiFe_xMn_(1-x)O_2的精细结构（英文）

利用共沉淀法合成出了一系列化合物LiFe_xMn_(1-x)O_2(0≤x≤1),电化学测试表明LiFe_(0.25)Mn_(0.75)O_2可逆容量最高,当倍率为0.1C(1C=140mA/g)时,可逆容量可达180mAh/g.通过X射线衍射(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线吸收谱(XAS)对所制备的材料的组成、形貌和精细结构进行了表征.XRD和XAS的结果显示LiFe_xMn_(1-x)O_2(0x1)含有三重晶体相即尖晶石相(LiMn_2O_4)、富锂相(Li_2MnO_3)和层状相(LiFeO_2).另外,XAS结果证明材料中的Mn相和Fe相是随机堆叠的.该研究表明Fe的替代影响了晶体相的组成和Mn相的局域结构,进而调节了该正极材料的电化学性能,得到当x=0.25时最优的电化学性能.     

C／BNxC2（1—x）、BN／NBxC2（1—x）和C／BN异质结价带偏移

彩和原子集团展开和平均键能相结合的方法，研究了宽带隙高温半导体，合金型应变层异质界面C／BNxC2(1-x)、BN/NBxC2(1-x)和生长在BN/NBxC2(1-x)合金衬底上的C／BN应变层异质结的价带偏移△Ev。结果表明：C／BNxC2(1-x)和BN/NBxC2(1-x)的△Ev随x的变化是非线性的，而应变层C／BN的△Ev随x的变化是接近于线性；三种异质结的△Ev值随x的变化关系决定于异质界面两侧带阶参数Emv随x的变化规律。     

三元混合晶体AxB1—xC中的极化子

本文讨论了弱耦合下三元混合晶体A_xB_(1-x)C中的极化子问题.在绝对零度下,用微扰法导出了极化子基态能量和有效质量表达式,对几种三元混合晶体进行了数值计算.在浓度x=0和x=1时,得出的结果与对应的二元晶体——BC,AC的结果完全等价.     

Mg_xZn_(1-x)Se合金的电子结构、光学性质和稳定性的第一性原理研究（英文）

基于密度泛函理论的第一性原理计算,研究了闪锌矿Mg_xZn_(1-x)Se合金的稳定性、电子结构和光学性质.研究结果表明,闪锌矿ZnSe和Mg_xZn_(1-x)Se合金都为直接带隙半导体,Mg_xZn_(1-x)Se合金的带隙宽度Eg和形成能Eb分别可以由Eg=1.30+1.34x和Eb=-1.48+0.60x-0.27x~2进行估计.同时,Mg_xZn_(1-x)Se合金的价带顶主要取决于Se 4p和Zn 3p态电子的相互作用,而其导带底则主要由Zn4s、Zn 3p以及Se 4s态电子共同决定.此外,随着镁掺杂系数x的逐渐增大,Mg_xZn_(1-x)Se合金的静态介电常数逐渐减小,而其吸收谱则出现明显的蓝移现象.研究结果为Mg_xZn_(1-x)Se合金在光电探测器方面的应用提供了重要的理论指导.     

计算混晶材料电子结构的超原胞统计法

提出了计算赝二元系(A_(1-x)C混晶材料任意组分电子结构的超原胞统计法,接替代格点数n选择超元胞,计算B原子数n_从零到n的所有超原胞电子结构为“样本”,结合以混晶键合性质决定的统计分布确定系统的电子结构,以(Ba_(1-x)K_)BiO_3为例,计算了x=0.2至x=0.5电子结构随组分的变化,结果表明,x>0.5的超元胞是不稳定的,费米面处总态密度TDOS(EF)随x变大而增加,与实验结果一致。     

Li[Li(1/3-x/3)Mn(2/3-2x/3)Cox]O2(x=O.1)的团簇自旋玻璃态行为

采用柠檬酸盐法制备了六方层状结构的Li[Li(1/3-x/3)Mn(2/3-2x/3)Cox]O2(x=0.1)材料.体系在高温区呈现顺磁态,通过拟合Curie-Weiss定律得到Curie和Weiss常数分别为1.70(2)m3 K/mol和-22(3)K.该材料的磁化率曲线在低温区表现出不可逆转变行为,并且这种不可...     

层状杂化材料M2（OH）4-x(C10H17O2)x·zH2O中有机官能团与无机金属的配位模式

运用红外光谱(IR)技术对嫁接了手性3,7-二甲基-6-辛烯酸的杂化材料M2(OH)(4-x)(C10H17O2)x·zH2O中有机官能团与无机金属的配位模式进行了分析和讨论。结果表明,有机-无机杂化材料M2(OH)(4-x)(C10H17O2)x·zH2O中,羧基官能团采取了二齿配位的连接方式,一端与无机金属连接,另一端通过氢键与羟基或者水键合。     

L1_2结构γ′-Co_3(Al_(1-x)W_x)相的弹性性质和热力学性质的第一性原理研究

采用第一性原理方法并结合准简谐德拜模型,系统研究了W原子分数对Co基高温合金中γ′-Co_3(Al_(1-x)W_x)(x=0,0.25,0.50,0.75,1.0)相的弹性性质和热力学性质的影响.研究发现随W原子分数的升高,γ′-Co_3(Al_(1-x)W_x)相的弹性模量显著提高,而弹性各向异性的程度明显降低,同时γ′-Co_3(Al_(1-x)W_x)相由延性材料向脆性材料过渡转变.通过分析电荷密度和态密度的计算结果,发现随W原子分数的增大,Co和W之间共价键的结合强度呈现增大的趋势,并且Co原子间的电荷密度分布逐渐由各向异性向各向同性过渡转变.在有限温度下,随W原子分数的升高,γ′-Co_3(Al_(1-x)W_x)相的热容、热膨胀系数和焓均减小.     

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