煅烧硫酸铝铵复盐低温合成α-Al2O3：葡萄糖和预压的影响

以NH₄Al(SO₄)₂·12H₂O为原料，通过加入不同质量分数的葡萄糖合成α-Al₂O₃，研究了葡萄糖含量和预压处理对α-Al₂O₃粉体合成工艺和温度的影响。结果表明：葡萄糖的加入可以明显改变相变过程，降低合成温度。添加质量分数为30%的葡萄糖时，可在950℃合成单相α-Al₂O₃粉体，合成温度比不添加葡萄糖时低200℃左右；添加质量分数为75%的葡萄糖时，α-Al₂O₃的合成温度可进一步降低至900℃。添加葡萄糖可以降低α-Al₂O₃合成温度的主要原因有两个：一是葡萄糖氧化分解产生的热加速了NH₄Al(SO₄)₂·12H₂O的热分解，二是葡萄糖的添加使NH₄Al(SO     

Na2SiO3/Fenton体系氧化脱除NO的实验研究

针对当前氧化法脱硝所需烟气停留时间过长的问题,采用Na₂SiO₃/Fenton脱硝系统进行了氧化脱除燃煤烟气中NO的实验研究．结果表明：该系统可以在烟气停留时间为3 s的条件下获得94.36%的NO脱除效率．最佳反应条件为：反应温度50℃,H²₂O₂浓度1 mol/L,Na₂SiO₃浓度0.06 mol/L,Fe⁺浓度0.01 mol/L．电子自旋共振技术和抑制剂添加实验说明：Na₂SiO₃的添加抑制了原Fenton系统中·OH自由基的生成,促进了O₂^-·自由基的生成并使其成为NO脱除的主要活性物质．除此之外,反应物(H₂O₂,Fe²⁺和Na₂SiO₃)初始浓度及温度增加对NO脱除具有一定的促进作用,但促进效果有限,而...     

固相反应制备Li2FeSiO4/C及嵌/脱锂性能研究

本文利用直接高温固相反应,合成制备了锂离子电池正极材料Li₂FeSiO₄及Li₂FeSiO₄/C,并研究了碳复合改性对Li₂FeSiO₄的结构、电导率、嵌/脱锂性能、循环比容量等方面的影响。结果表明,材料的制备工艺流程简单易行,有利于规模化生产;碳复合改性有利于提高硅酸盐正极材料的导电性能,改善材料在成相反应后的粒度分布;特别是碳复合改性有利于提高Li₂FeSiO₄的嵌/脱锂性能和循环比容量,Li₂FeSiO₄/C在0.1C倍率下首次放电容量高达120 mAh/g以上,大大高于未经复合改性Li₂FeSiO₄的20 mAh/g。研究表明,Li₂FeSiO₄是一种很有研究价值和开发潜力的锂离子电池正极材料,碳复合改性可显著克服该材料在电导率、电化学性能等诸多方面所存在的不足和局限。     

层状化合物K0.81Li0.27Ti1.73O4的合成

研究以K₂CO₃,Li₂CO₃和TiO₂为反应原料合成层状钛酸盐K_0.81Li_0.27Ti_1.73O₄过程中合成条件对产物的影响. 结果表明: 反应温度在
1 000~1 200 ℃, 反应原料配比为n(K₂CO₃) ∶n(Li₂CO₃) ∶n(TiO₂)=(0.405~0.42) ∶(0.135~0.165) ∶1.73时, 均可以得到产物K_0.81Li_0.27Ti_1.73O₄, 延长反应时间及升高反应温度均有利于产物的生成; 在1 200 ℃高温条件下, 使用刚玉坩埚为反应容
器时, 最佳的反应条件是： 反应温度为1 100 ℃, 反应原料配比为n(K₂CO₃) ∶n(Li₂CO₃) ∶n(TiO₂)=0.405 ∶0.135 ∶1.73, 反应24 h.     

锂离子电池电极材料Li4Ti5O12@TiO2的制备及性能

用水热法制备Li₄Ti₅O₁₂@TiO₂复合材料与同样方法制备的尖晶石型Li₄Ti₅O₁₂进行对比.对2种材料采用扫描电子显微镜、X射线衍射仪、光电子能谱仪(XPS)进行表征;N₂吸附-脱附曲线进行比表面积分析;恒电流充放电测试和电化学交流阻抗(EIS)技术进行电化学性能分析.结果表明Li₄Ti₅O₁₂@TiO₂和Li₄Ti₅O₁₂均呈颗粒状,粒径分别约为50和70 nm.XPS分析显示Li₄Ti₅O₁₂@TiO₂中的Ti为+4价态.电化学测试结果显示Li₄Ti₅O₁₂复合了锐钛型TiO₂...     

新法制备单相KZr2(PO4)3粉体

以氯化钾、磷酸二氢氨和八水氧氯化锆为原料,采用固相合成法,制备KZr₂(PO₄)₃粉体。对样品进行XRD(X射线衍射)、TG-DSC(热重分析-示差扫描量热)、SEM(扫描电子显微镜)测试表征,研究煅烧温度对粉体制备的影响。结果表明,煅烧温度800℃,煅烧时间为6 h,可以制备获得方块形貌的KZr₂(PO₄)₃纯相。     

PVC-Li4Mn5O12复合离子筛的锂吸附性能

采用PVC粘合成型技术对实验室合成的Li₄Mn₅O₁₂粉体进行成型,制备出直径约为3.5mm的球形PVC-Li₄Mn₅O₁₂复合材料,并通过SEM、孔径分布、吸附动力学和选择性测试等手段研究成型前后离子筛的形貌和吸附性能。结果表明:PVC-Li₄Mn₅O₁₂复合样品中的离子筛仍为纳米棒;且球形离子筛具有较大的比表面积,在模拟卤水中对Li⁺具有良好的选择性吸附性能。     

锆酸锂的合成及其吸收CO2性能研究

以纳米级四方相ZrO₂(t)为反应物,采用高温固相法合成了在高温下可直接吸收CO₂的Li₂ZrO₃材料。用扫描电子显微镜（SEM）、X-射线粉末衍射仪（XRD）分别分析了所合成材料的表面与结构特征,使用热重分析仪（TG）研究了Li₂ZrO₃材料吸收CO₂的性能。实验结果表明,吸收温度影响材料吸收CO₂的性能,500℃下Li₂ZrO₃材料具有最佳的CO₂吸收性能。此外,CO₂气体流量、Li₂ZrO₃材料样品重量以及升温速率均影响材料吸收CO₂的性能。     

通过构建Li2ZnTi3O8@LiAlO2复合物来实现高性能的储锂材料

立方尖晶石结构的Li₂ZnTi₃O₈（LZTO）具有成本低和安全性高的优势,被认为是代替碳材料作为锂离子电池负极材料的理想选择。然而,Li+和Zn2+离子位于LZTO的四面体位点,在一定程度上阻碍了离子的迁移,导致LZTO电导率差,锂离子扩散系数低。LiAlO₂的包覆有效避免了电极表面与有机电解质的接触,从而减少了副反应的发生。因此,本文采用简单的高温固相法合成了Li₂ZnTi₃O₈@LiAlO₂复合材料。结果表明:LiAlO₂改性未改变LZTO的形貌和粒径,但是提高了其结构稳定性、锂离子脱嵌的可逆性和电化学活性,促进了锂离子的迁移。Li₂ZnTi₃O₈@LiAlO₂ (8wt%)在0.5 C、1 C、2 C、3 C和5 C时的充电容量分别为203.9、194.8、187.4、180.6和177.1 mAh·g?1,表现出良好的倍率性能。然而,在相同的倍率下,纯LZTO仅有134.5、109.7、89.4、79.9和72.9 mAh·g?1的容量。即使在较大的充放电倍率下,Li₂ZnTi₃O₈@LiAlO₂(8wt%)材料也表现出良好的循环性能。在5 C倍率循环150次后后,Li₂ZnTi₃O₈@LiAlO₂(8wt%)仍具有263.5/265.8 mAh·g?1的充放电容量。LiAlO₂的引入增强了LZTO材料的电子导电性,使Li₂ZnTi₃O₈@LiAlO₂复合材料具有优异的电化学性能。     

SOFCs阴极材料La0.6Sr0.4Co1-x Fex O3-δ溶胶凝胶自燃烧法的制备

以分析纯La（NO₃）₃·6H₂为O、Sr（NO₃）₂、Co（NO₃）₂·6H₂O和Fe（NO₃）₁·9H₂O为原料,采用溶胶凝胶-自燃烧法制备了不同组成的La_0.6Sr_0.4Co_1-xFe_xO_3-δ（LSCF）超细粉体。采用X线衍射（XRD）和透射电子显微镜（TEM）对合成超细粉体的结构和形貌进行测定和表征。结果表明:溶胶凝胶-自燃烧法可一步合成粒径为30～70 nm的LSCF超细粉体,且随着Fe³⁺含量的增加,衍射峰值向低角度方向略有偏移。对超细粉体的烧结性能、热膨胀性能及电性能进行测试,结果表明:该粉体在1 100℃下烧结2 h,其相对密度达到97%。热膨胀系数随x(Fe³⁺含量)增加而增大,由x=0.1时的8.42×10^-6K^-1增大至x=0.5时的9.56×10^-6K^-1。直流四端子法电导测试表明:电导率随温度的升高（200～800℃）出现极大值,最大值可达950 S/cm,在500～700℃范围内,电导率均在200 S/cm以上,能够很好地满足中低温固体氧化物燃料电池对阴极材料的要求。     

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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