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1.
TiO2纳米晶的低温制备及其抗紫外线性能   总被引:2,自引:0,他引:2  
采用溶胶-凝胶法,在低温条件下制备纳米TiO2,用X射线衍射(XRD)对其结构和粒径进行表征,并测试分析了纳米TiO2溶胶对紫外-可见光的透射和吸收特性.结果表明,制得的纳米TiO2为锐钛矿型纳米晶,粒子尺寸小于10nm.纳米TiO2溶胶在波长250-350nm的紫外光区透射率极小,在220-340nm区域出现强吸收峰.将制得的纳米TiO2制成整理剂用于织物的整理.经过处理的棉织物对紫外线的阻隔率明显提高,紫外线防护指数(UPF值)从未处理时的6.72增加到50以上,表现出优异的抗紫外线性能.  相似文献   

2.
纳米ZnO/TiO2复合颗粒制备及紫外屏蔽性能研究   总被引:6,自引:0,他引:6  
以Ti(SO4)2和Zn(AC)2为原料,在制备金红石型纳米TiO2粉体的基础上,用溶胶凝胶法制得纳米ZnO/TiO2复合粉体.实验结合纳米TiO2和纳米ZnO的优点制得一种广谱防晒剂.TEM显示该复合颗粒为核一壳式结构;XRD分析该复合颗粒内核为金红石型TiO2,表面包覆一层六方晶系ZnO且该复合颗粒中存在强的化学键.UV-Vis测试表明该复合颗粒在整个紫外区的吸收能力达到85%,在UVA(320-400nm)区吸收性能比纯的TiO2强得多.  相似文献   

3.
纳米流体强化CO2鼓泡吸收实验   总被引:2,自引:0,他引:2  
利用两步法制备了多种乙醇基质纳米流体,建立了一套纳米流体强化气体吸收实验装置,分别测试了CO2在体积分数为0.01%-0.10%的Al2O3-C2H50H、MgO-C2H50H、SiO2-C2H5OH、TiO2(5nm).C2H50H、TiO2(25nm).C2H50H、Ti02(60nm)-C2H50H纳米流体中的吸收浓度曲线,得到了纳米流体的体积分数、纳米粒子的种类和粒径等因素对C02吸收过程的影响.实验结果表明,纳米流体的吸收强化效果随着纳米粒子体积分数的增加而增加,并且随着纳米流体中纳米粒子粒径的增加而减少.此外,还对纳米流体强化CO2吸收过程的机理进行了分析.  相似文献   

4.
以钛酸异丙酯为前驱体,反微乳法和溶胶-凝胶法相结合制备了TiO2纳米粉末,光还原法在TiO2表面沉积责金属Pt。用XRD、XPS对材料进行了表征。结果表明:TiO2为锐钛矿晶型,平均粒径约17 nm,沉积在TiO2表面的Pt主要以单质形式存在。少量以氧化态Pt^2+存在。光催化结果表明Pt/TiO2的光催化活性比纳米TiO2大大提高,用荧光光谱讨论了Pt/TiO2光催化活性提高的机理。  相似文献   

5.
Ti02纳米晶的低温制备及其抗紫外线性能   总被引:1,自引:0,他引:1  
采用溶胶一凝胶法,在低温条件下制备纳米TiO2.用x射线衍射(xRD)对其结构和粒径进行表征,并测试分析了纳米TiO2溶胶对紫外一可见光的透射和吸收特性.结果表明,制得的纳米TiO2为锐钛矿型纳米晶,粒子尺寸小于10nm纳米TiO2溶胶在波长250-350nm的紫外光区透射率极小.在220-340 nm区域出现强吸收峰.将制得的纳米TiO2制成整理剂用于织物的整理.经过处理的棉织物对紫外线的阻隔率明显提高,紫外线防护指数(UPF值)从来处理时的6.72增加到50以上,表现出优异的抗紫外线性能.  相似文献   

6.
以TiCl4La2O3、A1片为原料,采用液相共沉淀法制备了La2O3/Al2O3/TiO2纳米复合粉体,采用DSC—TG、XRD、TEM技术对该纳米复合粉体进行了表征.结果表明:纳米TiO2粉体经La2O3掺杂和Al2O3复合后,其耐温性能得到显著提高,该复合粉体经900℃煅烧后,粒径在32nm左右,锐铁矿含量约为77.2%(mool%)  相似文献   

7.
以钛酸正四丁酯及L-半胱氨酸为钛源和模板剂,醇热法仿生合成纳米TiO2前体,冉将前体与氢氧化钠溶液水热反应制备出TiO2纳米线.通过SEM、XRD、FTIR以及比表面积及孔径分析仪对前体及纳米线进行表征,结果表明:TiO2纳米线为无定型的钛酸盐结构,直径在20~40nm,长度达数微米,其比表面积为312.58m2/g;煅烧后TiO2纳米线由无定型转变成锐钛矿型结构,FT—IR图谱分析表明纳米线含有Ti—O键.  相似文献   

8.
通过溶胶-凝胶工艺制备了表面均匀的纳米TiO2光催化薄膜.用UV—Vis、AFM、XRD和XPS等对薄膜的表面形貌、结构和组成等进行了表征.结果表明,TiO2膜的表面均匀,颗粒大小约50nm,晶型为锐钛矿型.  相似文献   

9.
通过糠醛/8-羟基喹啉铝聚合物(PFQ)与纳米TiO2的复合制得了光活性很高的催化剂,并通过FTIR,UV-Vis,ESR等手段对光催化剂进行了表征.结果表明糠醛/8-羟基喹啉铝聚合物与纳米TiO2复合后,拓宽了纯纳米TiO2的光谱响应范围,使光催化剂在可见光范同都有很强的吸收.并用该催化剂对甲基橙进行了光降解反应,实验表明在自然光下,该催化剂十几分钟就能使甲基橙染料完全褪色.  相似文献   

10.
一次氧气对氢氧焰水解制备纳米TiO2颗粒的影响   总被引:2,自引:0,他引:2  
在氢氧焰燃烧合成细米TiO2时,一次氧气浓度直接影响燃烧过程性质、火焰的特征。通过调节一次氧气浓度,可以得到大小、形貌和晶型不同的纳米颗粒。在未达到化学计量比以前,φo2增加,二氧化钛一次粒子的粒度减小,粒度分布变窄,颗粒中的金红石含量显著下降。当四氯化钛进料浓度为0.47mol/m^3,φo2由0增加到0.10时,纳米TiO2颗粒平均粒径由70nm降到32nm,金红石的质量分数由0.93降到0.03。水解制备的TiO2颗粒为球形。  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.
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   

14.
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   

15.
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   

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.
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  相似文献   

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