MnOx/TiO2催化剂的制备及其低温NH3选择性催化还原NO性能

为了研究MnOx/TiO2催化剂的低温催化还原NO性能,采用微乳液法在不同的煅烧温度下制备了不同晶相的纳米TiO2,并以此为载体,利用浸渍法制备了一系列MnOx/TiO2催化剂.然后,利用BET,XRD,HRTEM,H2-TPR等方法研究了载体和催化剂的微观结构、分散状态和氧化还原性质.实验结果表明:随着煅烧温度的增加,纳米TiO2从锐钛型逐渐向金红石型转变,700℃煅烧得到的纳米TiO2呈混晶相,800℃煅烧得到的纳米TiO2则为纯金红石型;锐钛型及混晶相TiO2载体与活性氧化物MnOx之间的相互作用较为强烈,当纳米TiO2中金红石型与锐钛型并存时,MnOx优先与锐钛型纳米TiO2作用;纯金红石型纳米TiO2与MnOx之间的相互作用较弱.模拟NH3选择性催化还原NO的反应活性测试结果表明,500℃煅烧得到的MnOx/TiO2催化剂表现出较高的低温活性.     

溶胶-凝胶法制备不同晶相组成TiO_2及其可见光催化活性

采用溶胶-凝胶法制备了不同晶型的TiO2纳米粒子,以X-射线衍射、扫描电镜、红外光谱和紫外-可见固体漫反射吸收光谱对其进行了表征及光吸收特性研究,以可见光下TiO2对罗丹明B的降解率评价其光催化活性.结果表明TiO2纳米粒子的晶相分别为锐钛矿纯相、锐钛矿/金红石混晶和金红石纯相,粒子的平均粒径为10 nm左右,许多纳米粒子聚集形成较大的颗粒,且表面含有活性羟基.制备的三种晶相组成的TiO2对罗丹明B均具有较高的可见光催化活性,活性均高于商品TiO2（P25）,且活性按锐钛矿纯相、混晶和金红石纯相的顺序依次降低,可见TiO2的可见光催化活性与其晶相组成密切相关.     

溶胶-凝胶法制备不同晶相组成TiO2及其可见光催化活性

采用溶胶-凝胶法制备了不同晶型的TiO2纳米粒子,以X-射线衍射、扫描电镜、红外光谱和紫外-可见固体漫反射吸收光谱对其进行了表征及光吸收特性研究,以可见光下TiO2对罗丹明B的降解率评价其光催化活性.结果表明TiO2纳米粒子的晶相分别为锐钛矿纯相、锐钛矿/金红石混晶和金红石纯相,粒子的平均粒径为10 nm左右,许多纳米粒子聚集形成较大的颗粒,且表面含有活性羟基.制备的三种晶相组成的TiO2对罗丹明B均具有较高的可见光催化活性,活性均高于商品TiO2(P25),且活性按锐钛矿纯相、混晶和金红石纯相的顺序依次降低,可见TiO2的可见光催化活性与其晶相组成密切相关.     

纳米TiO_(2-x)N_x光催化薄膜的制备及其性能表征

采用溶胶-凝胶法制备TiO2溶胶,负载于玻璃微珠表面,并采用NH3气氛焙烧法制得掺氮纳米TiO2薄膜.运用X射线粉末衍射仪、扫描电镜和紫外-可见漫反射吸收光谱等技术,考察不同焙烧温度和负载次数对掺氮的TiO2样品性能的影响.研究结果表明,350,400,450℃热处理的样品的晶相为锐钛矿相,而在500℃时开始出现金红石相,且随温度的进一步升高,金红石相的含量逐渐增多;掺氮的TiO2样品具有可见光吸收性能,450℃热处理的样品达到最佳,其吸收边红移至约720 nm.另外,薄膜的厚度对样品的光催化性能影响显著,负载3次后,样品对罗丹明B的光催化活性最高.     

纳米多晶TiO2光催化性能的优化

研究了不同晶相组成的纳米TiO2对光催化性能的影响,以过滤纸为基材,通过真空过滤器,制备不同晶相组成的纳米TiO2.然后以甲苯为检测气体,通过光催化性能检测系统,测试了样品的光催化活性,得出具有最佳光催化性能的晶相组成为锐钛型/金红石型（质量比）=83/17,对进一步研究具有高光催化性能的光催化纸具有重要意义.     

金红石与针铁矿光催化材料结构与性能的关联

以TiCl4为钛源,针铁矿（α-FeOOH）为载体,采用水解沉淀法制备了金红石（TiO2）与α—FeOOH光催化材料．应用x射线衍射分析、扫描电子显微镜和透射电子显微镜对样品的晶相组成、形貌、微结构进行了表征．结果表明,制备温度对样品的晶相组成、形貌、颗粒大小和结构有明显的影响．随着制备温度升高．样品中α-FeOOH相的含量逐渐减少并最终消失,而金红石相TiO2的含量逐渐增加并最终全部金红石相TiO2;样品的形貌由棒状变为管状;复合材料的结构实现负载型→复合型→溶蚀复合型转变．应用紫外和模拟可见光谱对样品光性能进行了测试．样品对可见光的吸收得到了增强．在室温下以甲基橙为降解对象,分别在紫外光和模拟可见光照射下对样品光催化活性进行了评估．复合型和溶蚀复合型结构样品的活性均得到了不同程度的提高,而负载型结构样品的活性没有明显变化：在紫外及可见光照射下,样品对甲基橙的光催化降解效果较好,溶蚀复合型结构样品的活性最高．这说明样品的性能与结构有良好的关联性．     

氮掺杂暴露（001）面二氧化钛的制备及其可见光催化性能研究

以尿素为氮源、HF为调控剂,采用水热法制备了以（001）活性面为主的氮掺杂型TiO2催化剂.SEM、TEM、XRD、Raman及UV-Vis测试结果表明,TiO2及N-TiO2产品均为暴露（001）面的纳米片状锐钛矿结构,TiO2在高温900℃煅烧仍能保持锐钛矿结构.F-不仅对（001）面的暴露起到很好的调控作用,而且抑制了TiO2在高温下向金红石相的转化.氮的掺杂窄化了TiO2的禁带宽度,使其边带红移,在可见光区域有很强的吸收峰.并且,随着氮掺杂量的增多,N-TiO2在可见光的吸收峰增强.以可见光降解染料罗丹明B溶液作为探针反应,研究了不同N/Ti配比的N-TiO2的可见光催化活性,氮掺杂TiO2的可见光催化活性比照纯TiO2有明显的改善.     

掺氮光敏化纳米晶TiO2的研制

以四氯化钛、氨气或氨水为原料,醇为溶剂制备了掺杂氮的可见光敏化纳米晶TiO2,通过紫外可见吸收光谱验证了它具有良好的可见光吸收性能,吸收阚值最大可以达到830nm。XRD分析表明这种方法制备的TiO2为纳米金红石型或锐钛矿与金红石的混晶,制得的样品经350C热处理后比文献报道的在600℃处理的TiO2具有更好的可见光吸收。通过TG-DTA曲线、FT-IR、紫外一可见光谱图分析了氮的掺杂过程,指出前躯体中氮的存在形式以及氧化钛晶格中掺杂氮的存在状态对氧化钛的可见光敏化有重要影响。     

水热合成法制备特定形貌的二氧化钛及光催化性能

为考察TiO2的晶型和型貌对光催化性能的影响,分别以TiCl4和Ti（SO4）2为钛源,用水热合成法成功制备了金红石和锐钛矿型二氧化钛纳米晶,并对其进行了XRD、SEM、TEM、DRS表征．同时,以致癌性的活性染料X3B为目标分子,对催化剂的光催化性能进行了研究．考察了水热pH对催化剂的晶粒尺寸和形貌的影响,对TiO2晶形影响光催化活性的原因进行了探讨。     

二氧化钛纳米管阵列的制备及光催化效果的研究

用阳极氧化法制备出高度致密、有序的TiO2纳米管阵列.利用SEM和XRD表征分析纳米管阵列的形貌和结构.分析结果表明:经过450℃退火后的TiO2晶相结构为夹杂少量金红石相的锐钛矿相.以甲基橙在水溶液中的光催化降解为实例,分别研究了TiO2纳米管阵列在可见光和紫外光激发下的光催化性能.实验结果表明:该阵列在紫外光激发下有较高的光催化效率,但在可见光照射下产生降解效果不太明显.     

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     

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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Brief Introduction to “Journal of Jilin University( Science Edition) ”

<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has