CdO—Fe2O复合氧物半导体气敏材料的制备和性能

采用化学共沉淀法，制备了系列ＣｄＯ－Ｆｅ２Ｏ复合氧化物气敏半导体材料，研究了制备条件对电导和气敏性能的影响。     

新型乙醇气敏半导体材料CdFe_2O_4

采用化学共沉淀和固相反应相结合的方法制备出单相ＣｄＦｅ２Ｏ４，实验表明，ＣｄＦｅ２Ｏ４作为一种尖晶石型结构的复合氧化物，是电子导电型半导体，具有良好的酒敏性能．且有较好的化学稳定性和气敏稳定性     

亲型乙醇气敏半导体材料CdFe2O4

采用化学共沉淀和固相反应相结合的方法制备出单相ＣｄＦｅ２Ｏ４，实验表明，ＣｄＦｅ２Ｏ４作为一种尖晶石型结构的复合氧化物，是电子导电型半导体，具有良好的酒敏性能。具有较好的化学稳定性和气敏稳定性。     

新型气敏材料Cd2Nb2O7的制备和性能研究

采用固相反应法在９００℃下制备出具有烧绿石结构的莳地导体气敏材料Ｃｄ２Ｎｂ２Ｏ７，研究了制备条件对产物物相和气敏性能的影响，探讨了高温固相反应机理。电导测试表明：Ｃｄ２Ｎｂ２Ｏ７是一种典型的表面电阻控制型半导体材料；而气敏测试表明：Ｃｄ２Ｎｂ２Ｏ７对乙醇具有较高的灵敏度、较好的选择性以及快的响应恢复速度。     

YFeO3复合氧化物半导体材料的制备,掺杂和气敏性能研究

用化学共沉淀法制备了ＹＦｅＯ３及其掺锌固溶体Ｙ１－ｘＺｎｘＦｅＯ３气敏材料，并对其制备条件、相结构、电导和气敏性能进行了研究。结果表明：Ｆｅ与Ｙ物质的量比为１：１，８５０℃以上热处理一定时间可得钙钛矿结构的纯相ＹＦｅＯ３；电导测量显示，该系列材料呈ｐ型半导体导电行为，且固溶体导电优于纯相。Ｙ０．９４Ｚｎ０．０６ＦｅＯ３电导突变温度４００℃，较纯相ＹＦｅＯ３低７０℃，９００℃下热处理４ｈ所得微粉制作     

ZnO-CdO二元体系的导电机制和气敏效应￣①

采用化学共沉淀与固相反应相结合的方法，合成了一系列不同Ｚｎ／Ｃｄ比氧化物粉料。研究了不同Ｚｎ／Ｃｄ比对相结构、电导与气敏性能的影响．没有发现Ｚｎ，Ｃｄ氧化物形成明显的置换固溶体或第三相，但存在间隙固溶体现象。Ｚｎ／Ｃｄ比为８／２时，元件对Ｈ２和Ｃ２Ｈ２有较高的灵敏度和选择性。     

溶胶-凝胶法制备α-Fe_2O_3及其气敏性能研究①

采用溶胶－凝胶法制备了α－Ｆｅ＿２Ｏ＿３纳米材料，平均粒径在１０ｎｍ左右。并研究了α－Ｆｅ＿２Ｏ＿３的电学性能和气敏效应，发现掺杂降低了表面氧吸附－解吸活化能，提高了对还原性气体的灵敏度。据此推断α－Ｆｅ＿２Ｏ＿３气敏效应为表面控制型，并对其气敏机理加以探讨。     

溶胶—凝胶法制备α—Fe2O3及其气敏性能研究

采用溶胶－凝胶法制备了α－Ｆｅ２Ｏ３纳米材料，平均粒径在１０ｎｍ左右，并研究了α－Ｆｅ２Ｏ３的电学性能和气敏效应，发现掺杂降低了表面氧吸附－解吸活化能，提高了对还原性气体的灵敏度，据此推断α－Ｆｅ２Ｏ３气敏效应为表面控制型，并对其气敏机理加以探讨。     

掺锑α－Fe_2O_3超微粉材料的晶粒生长、微结构与气敏特性

用化学共沉淀法制得掺有一定量锑离子的α－Ｆｅ２Ｏ３，超微粉料．ＴＧ－ＤＴＡ、ＸＲＤ及ＳＥＭ等分析表明，掺锑量（Ｓｂ／Ｆｅ原子比）小于０．２时，材料仍保持α－Ｆｅ２Ｏ３的晶体结构，但其晶化温度随Ｓｂ含量的增加向高温区移动；在低温段纯α－Ｆｅ２Ｏ３的晶粒生长活化能（Ｑ＝１０．３ｋＪ／ｍｏｌ）远小于Ｓｂ／Ｆｅ＝０．１（Ｑ＝３５．３ｋＪ／ｍｏｌ）粉料的活化能；Ｓｂ５＋取代α－Ｆｅ２Ｏ３晶粒中Ｆｅ３＋格位与在４５０℃下长期工作粉料颗粒不易长大，是造成掺锑α－Ｆｅ２Ｏ３元件电阻降低一个多数量级及气敏性能显著改善的主要原因．     

类水滑石衍生镁铁混合氧化物的催化性能

采用共沉淀法合成镁铁类水滑石，以其为前体，制备了镁铁混合氧化物，并对样品进行Ｘ射线衍射分析，差热分析及比表面积测定，研究其对逆水煤气变换反应的催化性能，结果表明：催化剂前体具有类水滑石的层状结构，衍生得到的Ｍｇ／Ｆｅ（ｍｏｌ／ｍｏｌ）为１的混合氧化物在温度为６５０℃，ＣＬ２／Ｈ２（ｍｏｌ／ｍｏｌ）为４／１，Ｈ２空速为２８５０ｈ＾－１时催化性能最好，Ｈ２的转化率为７１．５％，ＣＯ的选择性近乎１００％     

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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