成型压力和掺杂对Na1.4Co2O4基材料性能的影响

采用溶胶-凝胶法制备了Na位掺杂Sr和Li(掺杂量分别为0.1,0.2,0.3和0.4)的Nal.4Co2O4基热电材料,研究了成型压力和掺杂对Nal.4Co2O4基材料电导率、Seebeck系数和功率因子等热电性能的影响.采用XRD分析了NaxCo2O4基热电材料的相组成.研究结果表明:掺杂Sr和Li制备的Nal.4...     

Ag,Er,Cu双掺杂对Ca3Co2O6热电性能的影响

采用溶胶 凝胶法和常压烧结技术, 制备一系列钴基氧化物热电材料Ca₃Co₂O₆和Ca_2.85M_0.15Co_2-yCu_yO₆(M=Ag,Er; y=0,0.1,0.2), 并通过X射线衍射(XRD)和扫描电子显微镜(SEM)考察样品的物相组成和微观形貌, 在300~1 000 K测定样品的电导率和Seebeck系数, 分析掺杂不同元素对复合物热电性能的影响. 结果表明: 制备的所有材料均为单一物相, 结构致密; 不同双掺杂元素对材料的热电性能均有提升作用; 当Ag⁺和Cu²⁺的掺杂量分别为0.15,0.2时, 可获得最优的热电性能, Ca_2.85Ag_0.15Co_1.8Cu_0.2O₆在965 K时的功率因子为71 μW/(K₂·m).     

Sm~(3+)掺杂纳米TiO_2的制备及其可见光光催化性能

采用溶胶-凝胶法制备Sm3+掺杂Ti O2催化剂,以可见光照下罗丹明B的光催化降解为模型反应考察其光催化性能。结果表明在煅烧温度500℃、Sm3+掺杂量1%时所制的Sm3+-Ti O2具有最优异的光催化性能。紫外可见漫反射(DRS)、扫描电镜(SEM)、X射线粉末衍射(XRD)、N2吸附-脱附(BET)等表征结果表明,稀土Sm3+的掺杂不仅使Ti O2的光吸收带边拓展至可见光区,而且抑制了Ti O2晶相由锐钛矿向金红石相的转变以及晶粒的烧结,增大了其比表面积,从而使Sm3+-Ti O2具有良好的可见光催化性能。     

n型CaMnO3基氧化物热电材料研究进展

n型CaMnO3基氧化物是一种具有优异高温热电性能的n型热电材料体系,从CaMnO3基热电氧化物晶体结构、物性、电子结构、电热传输理论以及Ca位掺杂、Mn位掺杂、Ca和Mn位复合掺杂优化其电热输运性能的角度,综述了n型CaMnO3基热电氧化物的最新研究进展,给出了存在的问题和今后研究的方向.     

Bi1.6Pb0.4Sr2CO2Oy/Ag复合块材高温热电性能

利用固相反应法制备了Pb-doped Bi2Sr2Co2Oy(Bi1.6Pb0.4Sr2 Co2Oy)/Ag多晶复合热电材料,并研究了Ag含量对样品结构和热电性能的影响.X线衍射和X线能谱分析表明,Ag主要以金属单质形式存在于Bi1.6Pb0.4Sr2Co2Oy中.适量的Ag(质量分数25％)复合能显著降低样品的电阻率,而对其塞贝克系数影响很小,从而使Bi1.6Pb0.4Sr2 Co2Oy的功率因子大幅提高;继续增大Ag的质量分数(30％),一方面会抑制Bi1.6Pb0.4Sr2 Co2Oy晶粒的生长,并使其c轴织构程度变差;另一方面会引起复合物中Ag颗粒的团聚、长大,导致其功率因子下降.Bi1.6Pb0.4Sr2 Co2Oy/Ag(质量分数25％)样品973 K时功率因子2.72×10-4 W/(m·K2),比相同温度下母体材料Bi2Sr2Co2Oy的功率因子提高了近60％.以上结果表明,在对Bi2Sr2Co2Oy掺杂的基础上同时进行金属Ag颗粒复合是提高其热电性能的有效途径之一.     

Sm_(1-x)Sr_xCoO_3陶瓷的制备及O_2气氛热处理对光热转换性能的影响

研究不同Sr掺量Sm1-xSrxCoO3陶瓷材料的制备及O2气氛热处理温度对产物光热转换性能的影响。研究表明:不同Sr2+掺杂浓度所合成的样品均为单一的钙钛矿结构,Sr掺量x为0.5时的发射率达到最小值(0.25)。Sm0.5Sr0.5CoO3样品经800℃O2气氛热处理后,产物能保持稳定的钙钛矿结构,且呈现较好的光谱选择性吸收性能,对应的温升效果最显著(15 min升高至400℃)。     

新型中温SOFC阴极材料Sm0.5Sr0.5VO4的制备与性能分析

为降低固体氧化物燃料电池(SOFC)的工作温度,发展新型中低温固体氧化物燃料电池阴极材料,采用固相反应方法,将元素Sr替代Sm进行掺杂制备一种新型阴极材料Sm0.5Sr0.5VO4.XRD谱图显示,在900℃下处理的样品形成了单相稳定的四方钙钛矿结构晶体,其晶格常数比没有进行掺杂的SmVO4晶格常数略微降低,说明Sr已经很好地掺杂进入SmVO4的晶格结构中;在650~750℃,单电池最大输出功率密度为209.5 mW/cm2,最大输出电流密度为138.3 mA/cm2.制备的阴极材料显示了良好的电化学性能.     

Na_xCo_2O_4热电材料的研究进展

介绍了NaxCo2O4氧化物热电材料的基本结构和热电性能,论述了NaxCo2O4热电材料的研究进展,并对NaxCo2O4材料的Na位掺杂(掺入K,Sr,Y,Nd,Sm,Yb,Ca,Ag)和Co位掺杂(掺入Ti,Rh,Pd,Pb,Mn,Ru)进行了评述·不同元素对Na位和Co位的掺杂效果的影响是不同的,但可以看出NaxCo2O4热电材料的掺杂研究有着非常好的研究价值和应用前景·     

高温固相法制备Sm2O3掺杂La2Ce2O7热障涂层材料

以La2 O3、CeO2和Sm2 O3为原料,采用高温固相反应法制备了Sm2 O3部分掺杂La2 Ce2 O7热障涂层陶瓷材料,其化学式为(SmxLa1-x)2Ce2O7.采用X射线衍射法研究了试样的物相结构,并通过对比各实验条件下制备的试样的X射线衍射图谱,对试样的掺杂比例、烧制温度及烧制时间进行了探究.结果表明,所制备试样为萤石结构,当掺杂摩尔比Sm：La为1：2或1：3时试样均能保持良好的相结构,以掺杂摩尔比Sm：La=1：2制备的( Sm0.33 La0.67)2 Ce2 O7材料在1600℃下具有良好的相稳定性,且其最佳制备条件为1550℃下烧制10 h,该材料是一种很有潜力的新型热障涂层陶瓷材料.     

H3BO3掺杂量对Sr3Al2O6:Eu,Dy红色长余辉发光材料性能的影响

采用高温固相法制备了Sr3Al2O6:Eu2+, Dy3+红色长余辉发光材料,研究了H3BO3掺杂量对其性能的影响.利用X射线衍射仪对材料的物相进行了分析,结果表明,1 200℃下制备的不同H3BO3掺杂量样品的物相为Sr3Al2O6 ;采用荧光分光光度计、照度计测定了样品的发光特性,结果表明Sr3Al2O6:Eu2+,Dy3+的激发峰位于472 nm的宽带谱,发射峰为位于612 nm的宽带谱,对应于Eu2+的4f65d1→4f7的跃迁;H3BO3的加入在促进产物晶化的同时,还可改变进入晶格中的Eu、Dy离子的浓度,从而改善余辉特性.余辉测试表明,Sr2.95Al1.8O6:0.02Eu2+,0.03Dy3+,0.2B3+的余辉时间最长,可达620 s(≥1 mcd/m2).     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

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