共沉淀法制备的铁酸锌纳米材料的晶化与晶粒生长行为

采用共沉淀法合成了纳米铁酸锌粉体,并对所制粉体在100~1000℃不同温度下进行热处理,用TEM、XRD等手段对所制备的纳米铁酸锌晶体进行了表征,并对纳米铁酸锌晶体的晶粒生长进行了探讨.结果表明,具有尖晶石结构的铁酸锌纳米晶在共沉淀反应时就已形成,但晶粒的尺寸较小;随着热处理温度的进一步升高,晶粒迅速长大,粒径的尺寸分布在5~30 nm;当热处理温度升至1000℃左右时,晶粒尺寸已达微米数量级.对照TEM和XRD测量结果,表明所制备的铁酸锌纳米粉颗粒为单晶颗粒.     

离子液体辅助制备粒度均匀的铁酸锌纳米粉体

以离子液体作为辅助反应介质,采用水热合成法制备了铁酸锌纳米粉体,并利用XRD和TEM研究了反应温度、压力和反应环境对铁酸锌晶相组成、粒度大小的影响.结果表明：制备的样品为纳米结构的单相铁酸锌,随着反应温度和反应环境的变化,半峰宽明显的不同;适当提高反应温度,能够明显地细化晶粒,促进晶粒形成;改变反应压力,对铁酸锌纳米晶粒形成有影响;在反应过程中添加适量的离子液体[EMIM]PF6,能够加速晶粒细化,有效促进铁酸锌纳米晶粒形成.     

SiO2掺杂对高温处理后纳米TiO2光催化性能的影响

以钛酸丁酯为原料,用醇盐水解法制备纳米TiO2,用SiO2掺杂纳米TiO2.并对高温处理后的掺杂纳米TiO2光催化活性进行研究。XRD和TEM研究结果表明,SiO2掺杂能有效的提高晶相转变温度,阻止TiO2从锐钛矿型向金红石型的转变和晶粒的长大。实验结果表明,在1050℃高温处理后,SiO2掺杂后的TiO2仍为锐钛矿型纳米晶体。用掺杂纳米TiO2对甲基橙的降解率来表征其光降解性能,SiO2掺杂TiO2在高温处理后依然具有较好的光催化活性,850℃处理后其甲基橙降解率由未掺SiO2时的11%提高到96.48%,晶粒尺寸则由50nm减小到20 nm.     

铽掺杂纳米二氧化钛的制备及光催化性能的研究

以Tb~(3+)掺杂纳米TiO_2为研究内容,采用溶胶-凝胶法合成不同Tb~(3+)掺杂量、不同煅烧温度的Tb~(3+)-TiO_2光催化剂.利用X射线粉末衍射(XRD)、红外(FT=IR)等现代分析技术对Tb~(3+)掺杂TiO_2纳米晶样品的结构进行测试、表征.以孔雀石绿溶液为目标降解物,研究了稀土Tb~(3+)掺杂量和煅烧温度对其光催化活性的影响.实验结果表明:Tb~(3+)掺杂纳米TiO_2能够细化晶粒,提高热稳定性;Tb~(3+)掺杂提高了TiO_2光催化活性.当煅烧温度为400℃时,Tb~(3+)-TiO_2=2.50%的催化剂,在自然光照射下,降解孔雀石绿溶液3h,降解率可达81.1%.     

La掺杂对纳米TiO2晶体结构的影响

采用溶胶凝胶法制备了纯纳米TiO2和稀土元素La掺杂纳米TiO2,利用XRD测试对其晶体结构进行表征.结果表明,二者均为单一锐钛矿相,晶粒尺寸均到达纳米级别,La掺杂后晶粒细化.     

铁掺杂TiO2纳米粒子光催化氧化庚烯的研究

采用新的合成路线制得掺铁TiO₂纳米粒子, 通过光催化降解庚烯研究其气固复相光催化性能, 用XRD, UV-vis和XPS等方法研究了掺铁TiO₂纳米粒子的晶体结构、 光吸收特性及表面化学形态. TiO₂纳米粒子掺杂Fe³⁺后, TiO₂的光吸收阈值发生红移, 向可见光区拓展; Fe³⁺掺杂浓度和焙烧温度对掺铁TiO₂纳米粒子的气 固复相光催化降解活性有很大影响, 实验结果表明, 掺铁量为0.5%(摩尔分数), 焙 烧温度300 ℃时光催化降解活性最好.     

石墨掺杂纳米TiO_2及其电催化性能研究

石墨掺杂TiO2可以有效延长TiO2电子-空穴对的复合时间,从而提高其电催化活性.采用溶胶-凝胶法并结合高能球磨法制备了石墨掺杂纳米TiO2,设计正交试验优化合成条件.用SEM,XRD表征了样品的形貌和晶体结构,用循环伏安法测试了TiO2粉末电极对亚铁氰化钾的电催化性能.结果表明:纯TiO2均为锐钛矿,晶粒尺寸随烧结温度的升高而增大,最大为27.3nm.掺入石墨过程中,为了不破坏石墨的晶体结构,球磨时间不宜超过2h.石墨掺杂纳米TiO2的氧化峰电流平均值最高为328.1μA,比纯TiO2提高了50.3%.影响石墨掺杂纳米TiO2电催化活性主要因素的大小顺序为石墨掺杂量球磨时间烧结时间烧结温度.     

双元素共掺杂纳米TiO2的制备及光催化活性

采用特殊液相沉淀法制备了双元素镧和铁掺杂纳米二氧化钛粉体,通过TG-DTA对其前驱体进行分析,用XRD和TEM对其进行表征.用它做催化剂在日光作用下对亚甲基蓝进行了光催化实验,结果表明双元素镧和铁掺杂纳米二氧化钛比纯纳米TiO2粉体光催化效果好.其中掺铁1%、镧0.5%的纳米TiO2在焙烧温度650℃焙烧时间30 min时效果最佳.     

双元素共掺杂纳米TiO2的制备及光催化活性

采用特殊液相沉淀法制备了双元素镧和铁掺杂纳米二氧化钛粉体,通过TG-DTA对其前驱体进行分析,用XRD和TEM对其进行表征.用它做催化剂在日光作用下对亚甲基蓝进行了光催化实验,结果表明双元素镧和铁掺杂纳米二氧化钛比纯纳米TiO2粉体光催化效果好.其中掺铁1%、镧0.5%的纳米TiO2在焙烧温度650℃焙烧时间30 min时效果最佳.     

TiO2纳米薄膜和TiO2／ZnFe2O4纳米复合薄膜的光学性能研究

用磁控溅射方法制备了ＴｉＯ２ 纳米薄膜和ＴｉＯ２／ＺｎＦｅ２Ｏ４ 纳米复合薄膜,研究了不同温度热处理和不同含量纳米铁酸锌对纳米ＴｉＯ２ 薄膜光学性能的影响。研究结果表明：用磁控溅射方法制备的纳米薄膜的厚度和晶粒尺寸均匀,并且随着热处理温度的升高而增大,掺杂纳米ＺｎＦｅ２ Ｏ４后ＴｉＯ２ 纳米薄膜的晶粒尺寸略有减小。ＸＲＤ 研究发现ＴｉＯ２／ＺｎＦｅ２Ｏ４ 纳米复合薄膜由非晶相向锐态矿相转变的温度高于纳米ＴｉＯ２ 薄膜。ＴｉＯ２ 纳米薄膜和ＴｉＯ２／ＺｎＦｅ２ Ｏ４ 纳米复合薄膜的光吸收边都随着晶粒尺寸的降低而发生蓝移,在相同热处理条件下,掺杂纳米ＺｎＦｅ２ Ｏ４ 后,纳米ＴｉＯ２薄膜的光吸收边发生了较大范围的红移,红移量随着掺杂量的增加而增大。通过热处理和掺杂纳米ＺｎＦｅ２Ｏ４ 可以实现对纳米ＴｉＯ２ 薄膜光吸收边大范围的调制。     

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