掺铁纳米ZnO粉体的软化学法合成及其表征

以ZnSO4、NH4HCO3、Fe2(SO4)3为原料,采用软化学合成法中的前驱物热分解法制备了不同掺杂量的纳米Fe3 -ZnO粉体.通过XRD对产物的晶体结构、晶粒大小进行了表征,并利用XRD、IR和TG-DTA对前驱物进行了表征.结果表明:前驱物为碱式碳酸锌Zn2(OH)2CO3,分解温度为300℃;产物为六方晶系纤锌矿ZnO,平均粒径在13.5 nm左右,掺杂的Fe3 已渗入到ZnO的晶格中.     

纳米ZnO的制备与表征

以ZnAc2.2H2O、(NH4)2CO3为原料,采用沉淀法制备了纳米ZnO.以TG-DTA、IR、XRD、TEM和BET等测试方法研究了纳米ZnO粉体的结构和形貌特性.结果表明,前驱物[Zn5(OH)6(CO3)2]经300℃焙烧2 h,得到的纳米ZnO为六方晶系,粒子为球形,最小晶粒约为5 nm,最大约为28 nm,大部分集中在16~20 nm之间,平均晶粒为19.4 nm,90%的纳米晶粒≤24 nm,粒度分布均匀,分散性良好.探讨了反应物浓度、物料配比和焙烧温度等对样品的影响.     

机械化学法合成纳米氧化锌研究

采用机械化学法合成了纳米ZnO粉体,利用DTS,XRD,FT IR,TEM等检测手段对纳米ZnO粉体进行表征;结果表明:经过PAA-NH4分散处理的ZnO粉体的分散性良好,粒径分布范围窄,在60~80 nm范围之间;XRD分析确认本实验所得粉体为纤锌矿结构的六方相ZnO,其纯度高,结晶度好.     

ZnO:Co粉体的制备及其电磁性能研究

目的 制备ZnO:Co粉体,并研究了不同Co掺杂浓度对ZnO:Co电磁特性的影响.方法 采用溶胶.凝胶法制备了ZnO:Co粉体,应用XRD,SEM等手段对产物进行了表征,用波导法测试了ZnO:Co粉体在x波段(8.2GHz～12.4GHz)的电磁参数.结果 各样品均为六方晶系纤锌矿结构的球状颗粒,当掺Co摩尔分数为5%时出现了微量的ZnCo_2O_4,XRD中3个主衍射峰对应的晶面间距随着掺杂浓度的增大而减小.从平均值的角度来看,各组样品具有较大的磁损耗,随着掺杂浓度的增大,ZnO:Co的介电参数(ε',ε"和tanδ_e)减小,而磁参数(μ',"μ和tanδ_u)先增大后减小.结论 此工艺条件下制备的ZnO:Co属于电磁损耗型微波吸收材料.     

ZnO/Sm-TiO_2纳米粉体制备及光催化性能

以钛酸四正丁酯为钛源,采用水热法制备Sm掺杂的纳米Sm-TiO2粉体.将ZnO引入到SmTiO2粉体中得到ZnO/Sm-TiO2粉体,研究不同焙烧温度、ZnO添加量对催化剂光催化性能的影响,确定最佳掺杂量及最佳焙烧温度;利用X射线衍射仪(XRD)、傅里叶变换红外光谱(FTIR)、扫描电镜(SEM)等测试手段对产物进行表征.结果表明:Sm-ZnO共掺杂能抑制TiO2由锐钛矿相向金红石相的转变,拓宽光催化剂的光谱响应范围,抑制了纳米晶体的生长;经掺杂后的TiO2纳米粉体的光催化性能有了明显的提高,在温度为400℃,Sm的掺杂质量百分比为0.2%,ZnO与TiO2的掺杂比为1∶8时所得样品的光催化效果最佳,甲基橙降解率可达96.34%.     

纳米ZnO粉体的制备

以ZnCl2为原料,以HN4OH为沉淀剂,采用液相沉淀法,制备出纳米级ZnO粉体.制得的纳米粉体粒径30nm左右,粒径分窄、分散性较好.在摩尔浓度变化的情况下,探讨了制备纳米级ZnO粉体的条件.     

纳米ZnO粉体的制备

以ZnCl2 为原料 ,以HN4 OH为沉淀剂 ,采用液相沉淀法 ,制备出纳米级ZnO粉体 .制得的纳米粉体粒径 30nm左右 ,粒径分窄、分散性较好 .在摩尔浓度变化的情况下 ,探讨了制备纳米级ZnO粉体的条件 .     

棒状氧化锌的制备及其光催化性能

以乙酸锌为锌源,水和乙二醇的混合溶液为溶剂,添加乙醇胺,采用溶剂热法制备了ZnO粉体,利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)对其晶体结构、形貌进行了表征,并以有机染料甲基橙溶液为目标降解物,考察了ZnO粉体的光催化性能,优化了其催化降解甲基橙的工艺条件.结果表明:制备出的ZnO为棒状六方系纤锌矿结构;在其用量为1.5g·L~(-1),甲基橙浓度为10 mg·L~(-1),紫外光照射40 min时,甲基橙的降解率达到99.8%,所制产品具有良好的催化性能.     

低温固相反应制备氧化锌微粉研究

以Zn(NO3)2、Zn(Ac)2、ZnCl2和Na2CO3为原料，通过低温固相反应方法制备出了ZnO超细粉体。讨论了制备过程中不同的反应体系、反应物配比、煅烧温度和保温时间对ZnO粉体平均粒径的影响，并对其作用机理进行了分析。实验结果表明：在低温下，固相反应能快速进行；以Zn(NO3)2和Na2CO3为反应体系，能得到结晶度好、分散性较好、平均粒径为20nm左右的ZnO粉体。     

片状ZnO纳米材料的制备及光学性能

ZnO是一种重要的金属氧化物无机半导体材料,其禁带宽度为3.37eV.以硫酸锌和硫氰酸钠为原料,以NaOH为沉淀剂,在超声波作用下采用液相直接沉淀法制备出了片状ZnO纳米粉体,反应在常温下进行.通过扫描电镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)、光致发光(PL)、光催化测试对产物的形貌、微结构和光学性能进行了表征.研究表明,制得的ZnO纳米片粉体材料具有缺陷态光致发光特性,并且有非常好的光催化活性.该制备方法简单、易于实现规模化生产.     

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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