钛盐水解制备纳米TiO2粉末的研究

以Ti(SO4)2水溶液为前驱体,NH3*H2O为沉淀剂,十二烷基苯磺酸钠(DBS)为表面活性剂,采用常温水解沉淀法制备出了纳米TiO2粉体.用XRD测试粉体的晶相组成;用TEM分析粉末的晶体形貌.研究了溶液的pH值、表面活性剂、煅烧温度等对纳米TiO2颗粒尺寸的影响.结果表明当溶液pH值为2.0～4.0,分散剂质量分数为1.5%时,水解得到的TiO2晶粒尺寸在10～20 nm之间.研究烧结过程中晶粒的变化时发现在煅烧过程中由于DBS的包覆有效地抑制了晶粒的长大.     

影响纳米TiO2粒径的工艺因素

采用均一沉淀法制备纳米TiO2.分析了影响晶粒径的工艺因素.研究表明通过改变反应物离子浓度、改变表面活性剂DBS和抑制剂H2SO4的加入量以及严格控制工艺参数.如反应时间、洗涤干燥方式和煅烧温度,可以获得颗粒均匀、分散性好的纳米TiO2.     

一步法合成纳米CeO2溶胶及其分散稳定机理

针对胶溶法制备纳半分散体时条件严格、过程繁琐的问题,以硝酸过量的Ce(NO3)3溶液和氨水为反应物,在低pH值条件下,通过一步法合成了在水介质和乙酸乙酯介质中稳定分散的亮黄色透明的纳米CeO2胶体分散体;讨论了表面活性剂(DBS)用量与萃取率的关系,得出了用乙酸乙酯萃取时Ce(NO3)3溶液与DBS用量的最佳比.电镜照片观察到,CeO2纳米粒子在水介质和乙酸乙酯介质中均呈球形,粒径分布均匀,平均粒径约为3～5nm.初步研究探讨了在两种介质中稳定分散的机理.     

纳米TiO_2颗粒的水解制备及其光催化性能研究

将钛酸四丁酯分别加入HCl、CH3COOH、NH3·H2O和NaOH溶液中直接水解,然后在500℃下空气中煅烧得到不同结构的TiO2纳米颗粒.用扫描电镜(SEM)、高分辨透射电镜(HR-TEM)、X射线衍射(XRD)、拉曼光谱对其结构进行了表征,用紫外可见分光光度计(UV)研究了不同结构的纳米TiO2颗粒对罗丹明B染料的催化降解行为.结果表明,直接水解得到的TiO2为锐钛矿相,其形貌随水解溶液的不同而不同.CH3COOH溶液中水解得到的纳米TiO2颗粒具有良好的光催化效果,这主要是由其优良的表面微观结构所致.     

影响纳米TiO2粒径的工艺因素

采用均一沉淀法制备纳米TiO2。分析了影响晶粒径的工艺因素。研究表明通过改变反应物离子浓度、改变表面活性剂DBS和抑制剂H2SO4的加入量以及严格控制工艺参数。如反应时间、洗涤干燥方式和煅烧温度，可以获得颗粒均匀、分散性好的纳米TiO2。     

水热法制备不同晶粒尺寸的纳米二氧化钛

以Ti(SO4)2为前驱体,H2SO4或NaOH为pH调节剂,通过水热法合成了不同晶粒尺寸的锐钛矿相纳米TiO2,并研究了反应体系的pH值、反应时间和Ti(SO4)2浓度对TiO2晶粒尺寸的影响。结果表明,纳米TiO2的晶粒尺寸与反应时间近似成对数关系,Ti(SO4)2浓度与反应体系的pH值对纳米TiO2晶粒尺寸的影响有近似线性叠加关系。通过对pH值、反应温度和Ti(SO4)2浓度的调节,可实现纳米TiO2的可控合成。     

前驱物沉淀法制备硅藻土/TiO2/TiOx的研究

采用溶胶-凝胶法将TiO2包覆在硅藻土(Diatomite)表面,并采用前驱物沉淀法制备包覆平整致密的硅藻土/TiO2/TiOx珠光颜料,探讨了pH值和煅烧温度对最终产物形貌的影响.结果表明:当溶液的pH值为5.0时,黑色钛氧化物颗粒细小,在珠光颜料表面分散比较均匀,包覆平整致密.650℃煅烧时,包覆粒子颗粒细小,包覆平整致密;700℃煅烧时,包覆平整致密,但包覆粒子尺寸较大.     

工业生产TiO2颗粒表面Al2O3包膜的研究

以尿素为沉淀剂,用强迫水解方法对工业生产TiO2颗粒表面进行了A l2O3包膜表面改性.研究了氧化钛粉体分散性与pH值关系,包膜pH、温度及陈化时间等影响.采用FESEM、XRD和Zeta电位仪进行表征,结果表明:在碱性条件下可以在TiO2颗粒表面获得较理想的A l2O3包膜;工业生产TiO2颗粒进行A l2O3包膜表面改性,包膜层晶体结构以γ-A l2O3为主,分散性和稳定性提高.     

纳米TiO_2对痕量Pb(Ⅱ)的吸附研究

利用TiO2纳米颗粒的表面吸附活性,应用火焰原子吸收光谱检测方法,高效分离了水中痕量的Pb(Ⅱ).系统研究了纳米TiO2的晶体结构、溶液的pH值、吸附时间、Pb(Ⅱ)的起始质量浓度对Pb(Ⅱ)吸附率的影响,得到纳米TiO2对Pb(Ⅱ)的最佳吸附条件为:pH=6.5,m(TiO2)=20 mg,ρ0(Pb(Ⅱ))=18 mg.L-1,t=90 min.测定了纳米TiO2对Pb(Ⅱ)的吸附等温线,应用Freundlich公式得到了吸附等温方程.     

ATO/TiO_2粉体的制备及导电性能研究

采用化学共沉淀法,制备Sb掺杂SnO2(ATO)包覆微纳米TiO2导电粉体,研究了不同的制备工艺条件对ATO/TiO2复合粉体电阻率的影响,得出最佳包覆方案:TiO2浆料浓度25%,m(SnCl4·5H2O)/m(TiO2)=25%,m(SbCl3)/m(SnCl4·5H2O)=12%,反应温度60℃,pH值1.5,包膜时间3h,煅烧温度500℃,煅烧时间3h;通过X射线衍射(XRD)、扫描电镜(SEM)等对表面包覆前后的微纳米ATO/TiO2的结构进行了分析表征.结果表明,ATO颗粒是以物理吸附的方式吸附在二氧化钛表面.     

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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