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1.
纳米二氧化钛光催化剂形态和活性的研究   总被引:2,自引:1,他引:1  
应用微乳液反应法合成水合 Ti O2 ,经煅烧获得纳米 Ti O2 粒子.采用 T E M 、 X R D、 B E T 比表面积测试等手段对粒子进行表征.结果表明,经650 ℃煅烧后粒子为锐钛矿型,平均晶粒尺寸为24.6 nm ,比表面积为53.8 m 2 /g,经1000 ℃煅烧后粒子为金红石型,平均晶粒尺寸为53.5 nm ,比表面积为20.3 m 2 /g.考察 Ti O2 粒子晶型对光催化降解苯酚溶液活性的影响,结果表明锐钛矿型纳米 Ti O2 光催化活性最高  相似文献   

2.
热处理对TiO2光催化活性的影响   总被引:16,自引:0,他引:16  
研究了热处理对TiO2粉末光催化活性的影响,结果表明,加热温度和加热时间是影响TiO2光催化活性最主要的因素,样品由非晶向锐钛矿型转变的温度为429℃;当600℃热处理5h,锐钛矿型与金红石型的比例为83/17时,TiO2的光催化活性最高。  相似文献   

3.
二氧化钛超细粒子的制备及其光催化降解含酚溶液   总被引:34,自引:0,他引:34  
采用非离子型W/O微乳液中水核作为“微反应器”制备水合TiO2,在不同温度煅烧得到形态不同的TiO2超细粒子;研究TiO2粒子作为光催化剂降解含酚溶液的催化活性。结果表明,前驱体煅烧温度对粒子光催化活性有明显影响,煅烧温度低、粒径小、比表面积大的粒子催化活性强;酚去除率随TiO2浓度升高而升高,但存在最大值;通入适量氧气有助于酚的去除,但通氧速率过大酚去除率反而下降;用酚氧离子在TiO2表面吸附机  相似文献   

4.
研究了用水热法制备纳米ZrO2-TiO2复合氧化物微粉。制备了ZrO2(C)-TiO2(A)。ZrO2(C)-TiO2(R),ZrO2(T)-TiO2(A),ZrO2(T)-TiO2(R)四组纳米复合氧化物及无定形的复合Zr-Ti水合氧化物。研究了它们的相变和可烧结性。经1400℃烧结10h得到了具有95%理论密度的ZrTiO4陶瓷。  相似文献   

5.
纳米TiO2材料的合成与特性   总被引:11,自引:1,他引:11  
用溶胶一凝胶法制得了纳米晶的TiO2粉未,采用热分析、X射线、透射电镜及红外吸收光谱技术研究了材料的结构及尺寸形貌在不同热处理温度下的变化规律.结果表明:TiO2干凝胶粉未在350℃热处理后晶态锐钛矿结构开始形成,而粉末的粒径增长缓慢;TEM显示平均颗粒大小为22nm.当热处理温度高于550℃时,TiO2晶粒迅速长大,并出现金红石结构的TiO2到750℃时,样品中所有的晶粒均转变为金红石结构.  相似文献   

6.
TiSiW12O40/TiO2催化合成葡萄糖五异丁酸酯   总被引:4,自引:2,他引:2  
报道了新型催化剂TiSiW12O40/TiO2催化酯化合成葡萄糖五异丁酸酯的糖酸比,催化剂用量,反应时间,反应温度褚因素对产率的影响。实验表明:TiSiW12O40/TiO2具有良好的催化活性,糖酸摩尔比为1:5.5,催化剂的用量为反应液的2%,酯化反应时间为2h,反应温度100 ̄105℃,反应产率可达89.6%。  相似文献   

7.
TiO2纳米粉体的制备及光催化活性   总被引:34,自引:0,他引:34  
以钛酸四丁酯为原料,采用溶胶-凝胶过程超临界干燥法制备了TiO2纳米粉 ,并通过XRD,BET,TEM等方法对所得样品进行了表征,制备的TiO2气凝胶具有很高的比表面积(488m^2.g^-1),平均粒径为4.6nm,具有锐钛矿型晶体结构,经500℃煅烧2h所得的纳米粉体,锐钛矿型晶体结构更为明显,平均粒径6.7nm,比表面积158m^2.g^-1。  相似文献   

8.
以TG-EGA等分析检测手段探明了云母钛颜料包膜层的组成,并对其热处理工艺作了系统的研究,得到了较佳的热处理工艺。同时以DTA,SEM,XRD技术研究了膜层TiO2粒子在煅烧过程中的形态及物相结合变化过程,结果表明,膜层的水合TiO2粒子在热重宫随着温度的升高逐步晶化,并由锐钛相向金红石相转化。  相似文献   

9.
液相沉淀法制备TiO_2超微粉末的影响因素分析   总被引:8,自引:0,他引:8  
利用TiCl4溶液和(NH4)2CO3饱和液反应生成Ti(OH)4沉淀,经洗涤、过滤、干燥、煅烧后制得TiO2超微粉末。根据成核生长的热力学和动力学原理,深入研究分析了共沉淀时温度、pH值、滴定速度和陈化时间对Ti(OH)4粒度的影响。研究结果表明,温度、pH值、滴定速度的影响较为突出,陈化时间的影响较小,煅烧温度对最终产品粒度和性能的影响是十分重要的,实验得出最优制备条件  相似文献   

10.
报道固体超强酸TiO2/SO4^2-作为催化剂进行了酸与异戌醇酯化反应的合成路线和工艺条件,实验结果表明;使用合适条件制备的固体超强酸TiO2/SO4^2-在135 ̄142℃,酸与醇比为1:2和适量(3%wt)催化剂下,反应1.5小时,丁酸异戌酯产率可达90%左右。  相似文献   

11.
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.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
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.  相似文献   

13.
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。  相似文献   

14.
王慧 《科技信息》2008,(10):240-240
Wuthering Heights, Emily Bronte's only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.  相似文献   

15.
The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.  相似文献   

16.
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.  相似文献   

17.
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-  相似文献   

18.
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-  相似文献   

19.
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  相似文献   

20.
<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  相似文献   

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