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1.
Sol-gel水热偶合法制备纳米AlOOH及其表征   总被引:1,自引:0,他引:1  
以AL2(SO4)3为原料,在pH值为3.5,溶胶浓度为0.3-0.5mol/L,分散剂0.3%,温度为80℃的条件下,胶溶4h,后经5h100-150℃的水热处理,制得平均粒度小于70nm的AlOOH;用TEM、X射线衍射、TG-DTA对样品进行了表征,并研究了不同介质、不同pH、不同分散剂用量对分散性能的影响。  相似文献   

2.
堇青石蜂窝陶瓷载体涂层的制备研究   总被引:3,自引:1,他引:2  
以拟薄水铝石为原料,HNO2为胶溶剂,制备AlOOH溶胶,并对堇青石蜂窝陶瓷载体进行涂覆.研究了拟薄水铝石含量以及HNO3的加入量对溶胶粘度、稳定性和涂层涂覆量的影响;比表面积法(BET法)测定堇青石蜂窝陶瓷载体涂层的比表面积;超声波振荡检测了氧化铝涂层的结合牢固度.结果表明,当拟薄水铝石质量分数为5%~8%,n(H^+)/n(AlOOH)=0.06~0.10时,可制得稳定的溶胶,且随着拟薄水铝石含量或HNO3加入量的增加,溶胶的粘度增加,涂层的涂覆量增大,拟薄水铝石含量对涂层的重现性及牢固度影响较小.  相似文献   

3.
超细改性A1OOH在PVC塑料中的应用研究   总被引:2,自引:0,他引:2  
本文研究了超细改性AlOOH阻燃剂在PVC塑料中的应用效果,考察了阻燃剂含量对材料的阻煤和力学性能的影响.实验结果表明,超细改性AlOOH有显著的抑烟作用,材料的阻燃性能达到难燃材料FY—0级,而且其力学性能有所改善.  相似文献   

4.
介绍了一种在常压和较低温度下制备针状勃姆石(γ-AlOOH)和Al2O3超微粒子的方法.以Al(OH)3胶体为前驱物,加入微量酒石酸钠和十二烷基磺酸钠作为形状和粒度的控制剂,经常压下回流加热,制备出针状超细勃姆石微粒,其长宽比约30nm:4nm.再经55℃2h锻烧后得γ-Al2O3超细粒子.用χ射线衍射、透射电子显微镜以及热重、差热等方法对产物进行了表征.  相似文献   

5.
溶胶凝胶和超临界干燥法制备纳米TiO_2粉体   总被引:1,自引:0,他引:1  
以钛酸丁酯 (Ti(OR) 4 )为原料 ,采用溶胶凝胶法及超临界流体干燥技术制备了纳米TiO2 粉体。采用正交设计法研究了操作条件对反应的影响 ,筛选出了最佳工艺条件。TEM检测表明 ,优化条件下制得的二氧化钛粉体粒径为 11~ 12 .3nm ,且随热处理温度的升高粒径变化不大 ,但团聚加重。XRD结果表明 ,当热处理温度为 5 0 0℃时晶粒为锐钛型 ;当煅烧温度为 80 0℃时晶粒转化为金红石型。BET结果表明 ,二氧化钛气凝胶颗粒的比表面积可高达5 5 6m2 /g ;但随煅烧温度的升高 ,比表面积下降迅速 ;在 5 0 0℃时 ,比表面积只有 94 .6m2 /g。  相似文献   

6.
采用沉淀法、溶胶凝胶水热法及一步水热法分别制备了3种AlOOH样品,运用XRD,BET,FT-IR,NH_3-TPD-MS和CO_2-TPD-MS等方法对样品进行了表征,同时将AlOOH与C302分层装填于固定床中进行CO加氢反应的活性评价。结果显示:不同方法制备的AlOOH会显著影响分层复合催化剂的产物分布,沉淀法有利于二甲醚的生成,而一步水热法有利于C_(2+)OH的生成。水热处理可以提高AlOOH的结晶度,其中晶型完整、择优取向晶面明显、具有适宜酸碱位的AlOOH有利于C_(2+)OH的生成。本研究为合成C_(2+)OH提供了新的思路。  相似文献   

7.
利用Al2O3粉末和水之间的水热反应合成了纯相-γAlOOH纳米晶.XRD、FTIR、TEM和TG-DSC等分析测试结果表明:在180℃水热反应10~24 h所得纯相-γAlOOH的形貌从开始的小方块状逐渐转变为薄片状;在200℃水热反应24h所得纯相-γAlOOH的形貌为薄片状.探讨了AlOOH纳米晶在该水热体系中的形成机理.  相似文献   

8.
超细氧化钴粉体的制备及表征   总被引:6,自引:0,他引:6  
用醇盐液热分解法制备超细氧化钴粉体,并用透射电镜对其表征,结果显示:该法可制得黑色、平均粒径为0.2μm的二维片状超细Co2O3粉。  相似文献   

9.
ACF/TiO2光催化膜制备及其降解活性研究   总被引:1,自引:0,他引:1  
采用溶胶-凝胶法经正交试验优化物料比后制得TiO2/ACF光催化膜,并用X-射线衍射对其结构进行表征;通过优化制备工艺参数,以及在紫外光作用下降解处理甲基橙废水,研究其光催化降解性能.结果表明:物料比为1:17.55:3.32:3.74:0.15(钛酸丁醣:无水乙醇:乙酰丙酮:去离子水:冰醋酸)、活化温度为350℃、焙烧3h,能制得二氧化钛呈锐钛矿晶体结构的光催化膜;处理浓度为400mg/L,pH值为4的甲基橙溶液,其脱色率达到98.3%,COD去除率达到86.2%.  相似文献   

10.
高比表面积超细二氧化硅粉体的制备   总被引:4,自引:0,他引:4  
以水玻璃为原料、乙酸乙酯为潜伏酸试剂 ,采用溶胶凝胶法制备出了高温润滑脂稠化剂———高比表面积超细SiO2 粉体。考察了乙酸乙酯用量和反应温度对成溶胶时间、SiO2 粉体BET比表面积及孔体积的影响 ,并用TEM、BET低温液氮吸附和IR等分析手段对SiO2 粉体颗粒进行了表征。结果表明 ,采用该方法制得的SiO2 粉体颗粒近似呈球形 ,粒径为 2 0~ 30nm ,比表面积均大于 40 0m2 /g ,最大比表面积可达 5 0 3 38m2 /g。较理想的反应条件为乙酸乙酯与水玻璃溶液中所含SiO2 的摩尔比为 0 8,反应温度为 5 0℃。  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.
<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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