气相水解法介孔分子筛MCM-41组装纳米TiO2研究

以水玻璃为硅源,表面活性剂十六烷基三甲基溴化铵为结构模板剂,合成出MCM-41介孔分子筛,并以钛酸丁酯为前驱体,在高温气相炉中进行水解,羟基缩合对介孔分子筛MCM-41进行了纳米TiO2的修饰。XRD、FTIR、N2吸附脱附、SEM表征手段对其结构特征的测试结果表明:纳米TiO2不仅进入介孔分子筛MCM-41介孔孔道,较均匀地修饰了介孔分子筛MCM-41的孔壁,而且使介孔分子筛MCM-41能够保持有序的孔道结构。     

MCM-48介孔分子筛的合成研究

本文以正硅酸乙酯(TEOS)为硅源,以十六烷基三甲基溴化胺(CTAB)为模板剂,用传统的水热合成法合成介孔分子筛MCM-48,探索模板剂、水、氢氧化钠等不同因素对合成MCM-48介孔分子筛的影响。在较低模板剂用量的条件下,合成了介孔分子筛,用XRD对MCM-48介孔分子筛进行了结构表征。     

中孔分子筛Al/SO_4~(2-)/MCM-41的合成与表征

用Al2(SO4)3对中孔分子筛MCM-41进行改性,制备了中孔分子筛Al/SO24-/MCM-41.采用X射线多晶衍射(XRD)、红外光谱(FT-IR)、N2吸附-脱附和NH3程序升温脱附(NH3-TPD)等测试技术对样品的结构和表面酸性进行了表征.结果表明,用Al2(SO4)3改性中孔分子筛MCM-41,能得到仍保持着六方介孔结构的中孔分子筛Al/SO24-/MCM-41.     

强酸性和水热稳定的MCM-41分子筛的合成

以ZSM 5沸石分子筛为原始硅铝源,在碱性条件下,通过水热法合成出了孔壁含有ZSM 5预结构单元的MCM 41介孔分子筛。采用XRD、N2 吸附脱附、FT IR和NH3 TPD等表征手段对样品进行分析,结果表明该分子筛是含有ZSM 5 沸石预结构单元的六方晶相结构,该介孔分子筛的孔壁明显厚于常规方法合成的MCM 41,具有较高的水热稳定性和较强的酸性。     

有样弱碱体系中合成序度介孔分子筛MCM—41

1992年Ｍｏｂｉｌ科学家合成出Ｍ41Ｓ系列介孔分子筛[1] ,拓展了分子筛材料在催化、吸附分离和功能材料制备等领域的应用范围 .在Ｍ41Ｓ系列介孔分子筛中 ,以六方介孔分子筛ＭＣＭ 41的应用前景最为广阔 .ＭＣＭ 41通常在碱性条件下合成 ,采用的碱介质多为氢氧化钠和四甲基氢氧化铵等强碱 ,并多在高温下合成 .然而 ,这样得到的样品其结构有序性和水热稳定性均不理想 ,尤其是用正硅酸乙酯作硅源合成的样品 .近年来 ,有文献报道用氨水、甲胺和乙胺等弱碱为碱介质进行了ＭＣＭ 41的合成[2 ] ,得到的样品不仅规整有序 ,而且水热稳定性也有所提高…     

化学工程与工艺专业创新实验——碱性水热法酸性制备MCM-41分子筛

MCM-41中孔分子筛具有相当大的潜在价值.该文在碱性条件下,采用水热晶化法,以硅酸钠为硅源,表面活性剂十六烷基三甲基溴化铵为结构模板剂,成功合成出MCM-41中孔分子筛.采用XRD,IR,TG等表征手段研究了合成条件(pH值),凝胶后处理条件(老化时问,晶化时间和焙烧温度)和碱介质的选择对MCM-41结构的影响.     

MCM-41/HY介-微孔复合分子筛的合成与表征

以介孔MCM-41凝胶为母液,通过滴加HY浆液,应用水热反应釜合成了一种介-微孔复合分子筛MCM-41/HY.通过XRD、BET、NH3-TPD等手段对复合材料进行了表征,并对复合分子筛的水热稳定性进行了考察.结果表明,复合材料同时具有介孔分子筛MCM-41和微孔HY型沸石的特征,并且和纯MCM-41分子筛相比,复合分子筛的酸性明显增强,水热稳定性显著提高.     

聚合物的添加对纯硅MCM-41结构及形貌的影响

以正硅酸乙脂(TEOS)为硅源、十六烷基三甲基溴化铵(CTAB)为表面活性剂、聚乙烯醇(PVA)和聚丙二醇(PPG)为助模板剂,合成MCM-41纯硅介孔分子筛,并运用N2吸附和TEM表征技术探讨其性质.结果表明:PVA加入后产物为正六边形形貌的单分散的纳米MCM-41,加入PPG后则生成较长的棒状MCM-41分子筛.     

在低表面活性剂浓度下合成含Y沸石次级结构单元的介孔分子筛

以表面Mol比很低(xsurf／xSiO2=0．07)的阳离子表面活性剂十六烷基三甲基溴化铵(CTAB)和阴离子表面活性剂(SL)的混合水溶液为模板，以具有Y沸石次级结构单元的溶胶为前驱体，在碱性条件下合成了孔道结构类似于MCM-41的介孔分子筛，样品的XRD、FT—IR、N2吸附-脱附、SEM等表征表明合成的介孔分子筛是孔壁含Y沸石次级结构单元的六角相结构，该介孔分子筛的孔壁厚于常规水热方法得到的MCM-41材料的孔壁，它的形貌有别于常规水热方法得到的MCM—41的疏松形貌，为网状交叉结构。对样品水热稳定性的考察显示，在600℃ 100％水蒸气下处理10h，仍然可以保持其中孔结构。     

新型功能化介孔材料CH3-MCM-41-NH2的合成和表征

以硅酸钠为硅源,十六烷基三甲基溴化铵（CTAB）为模板剂,合成介孔材料MCM-41．采用两步嫁接法,分别用三甲基氯化硅（TMSCL）和3-氨基三乙氧基硅烷（APTS）对合成的介孔分子筛进行化学修饰,首次将甲基和氨基同时嫁接到介孔材料MCM-41上,得到新型的介孔材料CH3-MCM-41-NH2．利用XRD和FT—IR对合成的新型功能化介孔材料进行表征．     

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.     

An Analysis of Catherine＇s Character——Wuthering Heights

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

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.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

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