海藻酸辅助溶胶-凝胶法制备球形氧化铝颗粒

以2种不同的拟薄水铝石(PB)和海藻酸钠(ALG)为原料,采用海藻酸辅助溶胶-凝胶法制备γ-Al2O3颗粒.用氮气吸附-脱附、强度测定仪、XRD、SEM、XRF对样品进行表征;考察了2种拟薄水铝石的胶溶指数;研究了不同拟薄水铝石配比及胶溶剂硝酸处理时间对氧化铝颗粒物化性质的影响.结果表明:拟薄水铝石的胶溶指数是影响颗粒强度的重要因素;采用不同的拟薄水铝石进行配比,可调控氧化铝颗粒的孔结构及强度;随着硝酸处理时间的延长,氧化铝颗粒的比表面积、孔容和孔径逐渐降低,钙含量也随之降低,但颗粒的强度随着处理时间的延长而增大,并在15,min时达到最大值104,N,继续延长处理时间强度出现一定程度的降低;硝酸处理过程改变了拟薄水铝石粒子的大小和堆积方式,并没有改变γ-Al2O3的物相结构.     

制备条件对拟薄水铝石晶粒度与孔结构的影响

采用反应结晶法,以偏铝酸钠、硫酸铝为原料,制备了一系列拟薄水铝石样品．用X射线衍射、氮吸附脱附、扫描电镜等方法分析了制备条件对拟薄水铝石晶粒度与孔结构的影响．实验结果表明：拟薄水铝石的平均晶粒度随pH值、温度及老化时间的增加而增加;较低pH值或温度下生成无定形凝胶,较高的pH值或温度下生成了薄水铝石或β-三水铝石;温度升高与老化时间增加可分别有利于大孔的形成与整体孔数量的增加;晶粒度较大的单一拟薄水铝石样品,其表面积与孔容也较大．在 pH 值为8.6、反应温度75,℃及老化时间2,h 的优化制备条件下,拟薄水铝石具有单一晶相,平均晶粒度为4.58,nm,比表面积为342,m2/g,孔容为0.533,cm3/g,平均孔径约为3,nm,形貌如绒毛球状．     

拟薄水铝石在催化剂制备中的应用研究进展

拟薄水铝石具有比表面积高、孔容大等特点,广泛用作氧化铝前驱体。综述了近年来拟薄水铝石在载体及催化剂、分子筛、吸附剂、复合材料等方面的应用,建议未来应注意针对不同催化反应,从改进拟薄水铝石的生产工艺入手,设计提供最优化的拟薄水铝石产品,保证产品质量的稳定性,减小环境污染,降低生产成本。     

浅谈石油勘探开发衍射物相分析

石油是一种液态的,以碳氢化合物为主要成分的矿产品。X射线衍射物相分析是鉴定和识别矿物的可靠方法。本文以GZ1井、Zh4井、W2块、Ch3块K2c油藏样品的X射线衍射物相分析为倒,说明该方法在石油勘探开发中应用的重要意义。     

掺杂CeO2氧化铝涂层的性能研究

在以拟薄水铝石胶溶法制备的AlOOH溶胶中加入CeO2粉末,制备物质的量组成为nCeO2：nAl2O3 =1：3的涂覆浆液,并对堇青石蜂窝陶瓷载体进行表面涂覆．利用X射线衍射（XRD）、比表面积（BET）等方法研究了CeO2掺杂对氧化铝涂层的晶相结构、负载量以及比表面积和孔径分布的影响．结果表明,CeO2掺杂抑制了介稳态γ-Al2O3向稳定态α-Al2O3的转变,增加了氧化铝涂层的负载量和比表面积,提高了氧化铝涂层的高温热稳定性．     

钆取代M型钡铁氧体的研究

采用草酸盐共沉淀工艺制备了组成为(χ/2)Gd_2O_3+(1-χ)BaO+6Fe_2O_3的草酸盐粉料,预烧、成型后在不同温度下进行烧结。用热中子透射法测定了样品中的含钆量。用 X 射线衍射物相分析和磁分析方法研究了烧结过程中生成物的相组成及其相变。当χ≤0.12时,在1310℃烧结得到纯 M 相。在1400℃烧结得到的样品中,当χ≤0.15时为 X 相;当0.4≤χ≤0.6时主要相为 W 相。测量了样品的磁性、电阻率和 M(?)ssbauer 谱。发现在 X 结构化合物中,室温下的磁晶各向异性常数随含钆量的增加而增加;W 相化合物的居里温度比文献报导的数据高80℃左右。讨论了在含钆的 M 型六角铁氧体中,Gd~(3+)对磁性和电阻率的影响,以及 Gd~(3+)和 Fe~(3+)间的交换作用。     

YB-10Al铝合金物相组成和断口形貌分析

【目的】研究YB-10Al铝合金的物相组成和断口形貌,分析掺杂对合金结构和性能的影响。【方法】利用X射线粉末衍射仪和带能谱的扫描电子显微镜研究两组不同成分的YB-10Al铝合金的物相组成及断口形貌。【结果】YB-10Al铝合金所含物相有Al(主要相)、Al N(少量)、Si(少量)、Fe(微量)等,且两组样品所含物相略有差异;合金断口形貌显示为浅而小的韧窝。【结论】YB-10Al铝合金试样为韧性断裂,断裂机制为微孔聚集型。     

呼和浩特市部分地区水垢的X-射线衍射物相分析

水垢给工农业生产和人们日常生活带来许多危害 ,为了防止和消除水垢 ,人们进行了长期的研究 ,总结出很多除垢方法[1] .实践证明 ,正确地了解水垢的物相结构 ,可以有针对性地采取措施 ,提高除垢效率 .本文用Ｘ -射线衍射法分析了呼和浩特市部分地区水垢的物相结构 ,旨在为防止和消除水垢提供实验依据 .实验用样品取自呼和浩特市南门外、旧城和铁路北 3个地区的民用烧水设施 ,标号分别为 1 #、2 #、3#.用Ｙ4Ｑ型Ｘ -射线衍射仪分别对样品作Ｘ -射线衍射 (ＸＲＤ)图 .表 1给出了 3个样品的部分衍射数据 ,样品的ＸＲＤ图见图 1 .表 1　 3个样品…     

X射线衍射技术及其在材料表征实验的研究综述

X射线衍射技术是一种不损害材料、无污染、精确测量并能得到样品完整结构信息的测量技术,在材料研究的众多领域得以应用。该文主要介绍了X射线衍射的产生及其工作原理,从物相分析、应力测量、晶粒尺寸和结晶度测量等方面概述了该技术在材料结构表征中的应用。     

两个满足性质W(G)=W(L(G))的双圈图

一个图G=(V,E)的Wiener指数W(G)是基于距离拓扑指标定义的图G中所有点对距离的总和,这篇文章我们给出两个满足性质W(G)=W(L(G))的双圈图,这里L(G)是图G的线图。     

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.     

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.     

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     

On the Thermodynamic Limit for Responses to Static Electromagnetic Fields

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     

Call for Papers

<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     

Journal of Donghua University ( English Edition) Contents of Volume 31

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