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1.
在乙二胺介质中以TBOT为钛源,TEOS为硅源合成了Ti-MCM-41中孔分子筛.采用TEM、XRD、FT-IR、TG-DTA等技术对其结构进行了表征.结果表明,EDAL/SiO2摩尔比在0.5~9.0的范围内均可制得结构规整的Ti-MCM-41分子筛;当EDA/SiO2=1.0时,分子筛样品的结晶度最高.由TG曲线可知,随着EDA/SiO2摩尔比的增加,分子筛的失重量呈现增大趋势.  相似文献   

2.
分别以正硅酸乙酯(TEOS)和Na2SiO3为硅源,室温合成了Cu∶Zn∶Al∶Si摩尔比为6∶3∶5∶100的类MCM-41催化剂,以XRD、N2吸附、氨吸附量热及异丙醇脱水/脱氢反应等表征了催化剂的性质.结果表明,两种催化剂均具有较好的介孔结构,以Na2SiO3为硅源的催化剂具有较强的酸性.甲醇水蒸气重整反应表明,以TEOS为硅源的催化剂对甲醇转化率和H2选择性均高于以Na2SiO3为硅源的催化剂.  相似文献   

3.
锐钛矿型TiO2/SiO2复合氧化物的制备   总被引:1,自引:1,他引:1  
以硅灰石为硅源、 硫酸钛为钛源, 在未添加任何表面活性剂的制备条件下得到较高比表面积的多孔锐钛矿型TiO2/SiO2复合氧化物.反应过程中生成微溶于水的CaSO4, 在复合物孔隙的形成中起重要作用. 利用XRD,TEM,N2吸附和脱附对复合物的微观结构和化学组成进行了表征.  相似文献   

4.
以Ce(NO3)3·6H2O为铈源、Zn(CH3COO)2·2H2O为锌源、聚丙烯腈为载体,运用静电纺丝技术结合高温焙烧制备了Ce掺杂的ZnO(Ce/ZnO)纳米催化剂.采用扫描电镜、热重分析仪、X-射线衍射对制得的复合纳米材料的结构进行分析,并对其光催化降解孔雀石绿的性能进行研究.研究结果表明:在制得的催化剂样品中C...  相似文献   

5.
以钛酸四丁酯为钛源,钨酸钠为钨源,无水乙醇为溶剂,乙酸作为抑制剂,采用同步法制备不同WO3掺杂量的TiO2粉体,即WO3/TiO2复合体.以罗丹明B水溶液作为目标降解物,考察了制备条件及降解条件对WO3/TiO2光催化性能的影响.结果表明,WO3/TiO2的最佳制备条件为:WO3掺杂量为5%(质量分数),焙烧温度500℃、焙烧时间2h.最佳光催化降解条件为:粉体投加量为7.5g/L,光照时间2.5h,初始溶液的pH=1.  相似文献   

6.
以钛酸正丁酯为钛源,用溶胶—凝胶法制备了活性炭负载TiO2光催化剂.以18W的紫外灯做光源,用制得的TiO2/AC催化剂降解工业含酚废水.综合分析了TiO2/AC催化剂对含酚废水降解效果的影响.结果表明:在相同反应时间下,TiO2/AC催化剂的降解效率明显高于TiO2催化剂.  相似文献   

7.
锐钛矿制备钛硅分子筛ETS-10及其表征分析   总被引:1,自引:0,他引:1  
研究了在无氟离子条件下以锐钛矿为钛源,硅酸钠为硅源,以水热法制备钛硅分子筛ETS-10的合成工艺,采用XRD、扫描电镜、热重分析、氮气吸附-脱附等不同分析方法对制备的ETS-10的形貌及性质进行表征分析.结果表明,产物中ETS-10的结晶度良好、成规则的截菱锥形,颗粒大小均匀,为微孔结构,孔径分布均匀,约为0.7 nm,BET比表面积和孔容较大,分别为333 m2/g和0.21 cm3/g.本实验制备的ETS-10含有少量的未反应锐钛矿杂质,但其对CO2,CH4及N2的吸附性能与传统法制得的ETS-10相似,且产物对CO2/N2的吸附选择性较高,可应用于烟道气中CO2的分离和回收.  相似文献   

8.
以二水合钼酸钠(Na_2MoO_4·2H_2O)、四水合钼酸铵((NH_4)_6Mo_7O_(24)·4H_2O)作为钼源,硫脲(NH_2CSNH_2)为硫源,葡萄糖为碳源,采用水热法制备了二硫化钼(MoS_2)/C复合材料。通过X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线光电子能谱(XPS)等分析方法对MoS_2/C复合材料的结构和形貌进行了表征,并对其电化学性能进行测试。结果表明:水热法合成的两种复合材料均为纳米片无序堆叠而成的蠕虫状结构,其中钼酸钠为钼源时呈微球状。将其用作负极材料时,钼酸钠作钼源性能更佳,其在电流密度为200 m A/g的情况下首次放电比容量为766 m Ah/g,库伦效率为78.3%,循环100次后容量保持在524 m Ah/g左右,其倍率性能优异。  相似文献   

9.
采用水热法,以Ti(SO4)2为钛源,NaCl为氯源制备了具有高催化活性的氯掺杂二氧化钛(Cl/TiO2)光催化剂.X射线衍射(XRD)、透射电子显微镜(TEM)和紫外可见漫反射光谱(DRS)等手段对样品进行表征.结果表明,焙烧温度、氯投加量等都影响Cl/TiO2光催化剂的光催化活性.750℃焙烧、氯投加量为15%(与钛的物质的量比)时的Cl/TiO2具有最佳的光催化活性,其平均粒径大小为67.O nm,比表面积为9.3 m2/g.该催化荆是锐钛矿和金红石相的混晶,其中锐钛矿含量为74.1%.苯酚降解实验表明:该催化剂的光催化活性高于商品二氧化钛P-25,200 min光照时苯酚的降解率可达90.6%.  相似文献   

10.
新型介孔分子筛Sr-MCM-41的合成及其吸附性能的研究   总被引:1,自引:0,他引:1  
 在碱性条件下,以十六烷基三甲基溴化铵为模板剂,正硅酸乙酯为硅源,硝酸锶为无机源,用水热法合成了新型介孔分子筛Sr-MCM-41,对其用AFM,XRD进行了表征,结果表明:产物在小角散射区内出现衍射峰,可以确认其中存在介孔结构.产物中大部分是海绵状的介孔物质,属于缺乏长程有序的晶相排列.并研究了其对2种水溶性染料甲基紫和碱性品红的吸附性能.介孔分子筛Sr-MCM-41对甲基紫和碱性品红溶液的吸附均符合Freundlich吸附等温式.最大吸附量分别为186mg/g和172mg/g,具有较好的脱色能力.  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.
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   

15.
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   

16.
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   

17.
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   

18.
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   

19.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  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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