纳米纤维素增强聚苯胺复合材料的制备及性能

为制备一种新型聚苯胺导电复合材料,以盐酸作为掺杂酸,过硫酸铵作为氧化剂,采用原位聚合法,将从废报纸中提取的纳米纤维素与苯胺单体复合,合成了纳米纤维素增强聚苯胺导电复合材料。分别利用傅里叶红外光谱仪(FTIR)、扫描电镜(SEM)、四探针测试仪、万能力学实验机,测试纳米纤维素增强聚苯胺导电复合材料的化学成分、微观结构、导电率、力学性能。结果表明,当聚苯胺的质量分数达到20%时,掺杂纳米纤维素的聚苯胺复合材料保持了良好的导电性能,同时提高了韧性。     

纳米纤维素增强聚苯胺复合材料的制备及性能

 为制备一种新型聚苯胺导电复合材料,以盐酸作为掺杂酸,过硫酸铵作为氧化剂,采用原位聚合法,将从废报纸中提取的纳米纤维素与苯胺单体复合,合成了纳米纤维素增强聚苯胺导电复合材料。分别利用傅里叶红外光谱仪（FTIR）、扫描电镜（SEM）、四探针测试仪、万能力学实验机,测试纳米纤维素增强聚苯胺导电复合材料的化学成分、微观结构、导电率、力学性能。结果表明,当聚苯胺的质量分数达到20%时,掺杂纳米纤维素的聚苯胺复合材料保持了良好的导电性能,同时提高了韧性。     

聚苯胺/氨纶复合导电纤维的制备工艺探讨

采用“现场”吸附聚合法制备聚苯胺／氨纶复合导电纤维。重点讨论聚合条件的改变，对纤维导电性能的影响，以获取制备聚苯胺／氨纶复合导电纤维的最佳工艺。研究结果表明：氧化剂的用量、掺杂剂浓度、苯胺单体浓度对纤维导电性能影响较显著；而反应时间、温度对纤维的导电性能影响不大。并对该导电纤维的力学性能进行了研究，结果表明，该纤维基本上保留了原有的力学性能，可进行下一步加工。     

煤/聚苯胺复合材料制备方法研究进展

煤基聚苯胺复合材料是以煤为模板,引入苯胺原位聚合制得的导电高分子材料,具有良好的光电性能、氧化还原性和可加工性,应用于防腐蚀、抗静电、二次电池、电极材料和电磁屏蔽等领域.文中综合阐述了近年来煤基聚苯胺制备方法的研究进展,对煤/聚苯胺复合材料制备方法如苯胺抽提/溶胀法、氧化处理法、磺化处理法等做了介绍,探讨了各种处理方法对煤和煤基聚苯胺结构和性能的影响,分析总结了现有方法制备的聚苯胺复合材料的优缺点,并对今后的研究方向作了展望.     

原位聚合制备聚苯胺/石墨烯导电复合材料的工艺

采用盐酸（HCl）为掺杂酸、以聚乙烯基吡咯烷酮（PVPK90）为空间稳定剂,在过硫酸铵（APS）氧化体系中通过原位聚合制备了聚苯胺/石墨烯导电复合材料。该方法制备的聚苯胺/石墨烯复合材料导电性能好,聚苯胺尺寸大小均一、形貌规整。实验结果表明,当石墨烯的添加量为7%（质量分数）时,聚苯胺/石墨烯复合材料的电导率较纯聚苯胺的提高了2个数量级。另外,对原位聚合制备聚苯胺/石墨烯复合材料的制备工艺进行了优化。对制备工艺进行优化后,在石墨烯添加量为1%（质量分数）时,聚苯胺/石墨烯复合材料的电导率较纯聚苯胺提高了一个数量级,在提高复合材料导电性的同时简化了加工工艺,大大提高了生产率,具有可靠的实用价值。     

胶乳反应改性法制备炭黑填充型丁腈橡胶复合材料

在以丁腈橡胶(NBR)胶乳、炭黑(HAF)为主的体系中，通过引入适当的单体——甲基丙烯酸甲酯(MMA)或丙烯酸丁酯(BA)，利用单体对橡胶乳液的接枝，与HAF表面产生化学结合，从而改善了炭黑在橡胶中的分散性，加强了橡胶与炭黑之间的结合，制备出了具有优良力学性能和耐热性能的炭黑填充丁腈橡胶复合材料．文中还考察了NBR、HAF与单体的接枝效果，并对复合材料的力学性能、热性能及动态力学性能进行了研究，通过扫描电镜(SEM)探讨了复合材料的微观结构、     

MWNTs/掺溴聚苯胺复合材料导电性能研究

用化学氧化法和溴蒸气掺杂合成掺溴聚苯胺,通过机械共混制备MWNTs/PANI和MWNTs/掺溴PANI复合材料.复合材料表现出良好的导电性能,电导率达5～10 S·m~(-1),接近纯MWNTs的电导率.采用红外光谱、热重分析、紫外可见光谱、X射线粉末衍射和X射线光电子能谱研究MWNTs/掺溴PANI复合材料的导电性能和导电机理.研究表明,MWNTs和被掺杂的掺溴PANI通过π-π和p-π共轭作用形成电子转移复合物,组成了一个个独立导电单元,在复合材料的导电体系中起主要作用,随着导电单元数量增加至相互接触,形成导电网络,复合材料的电导率达到最大值.     

混炼工艺和热处理对炭黑填充丁腈橡胶电学性能的影响

研究了混炼工艺和热处理对炭黑／丁腈橡胶复合材料导电性能的影响，实验结果指出，在速和辊距的条件下，混炼时间小于或超出某一范围对复合材料的导电性不利，同时使其ＰＴＣ（正温度系数）效应丧失，热处理使复合材料的室温电阻率下降，使复合材料导电稳定性得到改善。     

聚苯胺的化学合成、结构及导电性能

导电聚苯胺是结构和性能最稳定的导电高分子材料，有较广泛的应用前景。本实验用化学氧化合成方法，较系统地研究了氧化剂种类、用量、介质酸的浓度以及聚合反应温度等因素对苯胺聚合反应及产物性能的影响；找出了最适宜的合成反应条件和特殊的后处理工艺，并合成出了电导率高达３０．６５Ｓ／ｃｍ，收率达１２７．８％的高性能导电聚苯胺     

导电聚苯胺/TiO2复合纳米纤维的制备和表征

在无模板条件下,利用苯胺在纳米TiO2微粒表面的原位化学氧化聚合,成功制备了一系列不同TiO2含量的导电聚苯胺/TiO2(PANI/TiO2)纳米复合材料.通过TEM,XRD,FT-IR,TG-DTA及电导率测量等技术手段对其进行了表征.结果表明:复合材料的形貌呈纤维状,直径约20~40 nm,长度在390~420 nm范围;其中TiO2的含量为23.8%且具有金红石矿结构,聚苯胺也有一定程度的晶化;在复合材料中,TiO2和聚苯胺分子链之间存在强的相互作用,并对复合材料的热稳定性起促进作用;TiO2的含量对复合材料导电性能有显著影响,当TiO2含量为11.1%时电导率达到极大值2.86 S/cm.     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Perspherical Approaches for Electrons in Atoms and Charged Excitons in Quantum Wells

Instead of following Fock’s expansion,we solve the Schrodinger equation for some quantum mechanical manybody systems such as electrons in atoms and charged excitons in quantum wells in a similar way in hyperspherical coordinates by expanding the wave functions into orthonormal complete basis sets of the hyperspherical hannonics(HHs)of hyperangles and generalized Laguerre polynomials(GLPs)of the hyperradius.This leads the equation to     

Advances in broadband wireless communications under high-mobility scenarios

Future mobile communication systems aim at providing very high data transmission rates, even in high-mobility scenarios such as high-speed wheel-track trains, maglev trains, highway vehicles, airplanes, guided missiles or spacecraft. A particularly important commercial application is the strong and increasing worldwide demand for high- speed broadband wireless communications （up to 574.8 km/ h test speeds or 380 km/h commercial speeds） in railways, providing data, voice and video services for applications such as onboard entertainment services to passengers, train control, train dispatch, train sensor status handling and sur- veillance. In such high-mobility scenarios, there are a number of communication challenges, including fast hand- over, location updating, high-speed channel modeling, estimation and equalization, anti-Doppler spreading tech- niques, fast power control, and dedicated network architec- ture. Because signal transmission in very high-speed scenarios will inevitably experience serious deterioration, it is imperative to develop key broadband mobile communi- cation techniques for such high-speed vehicles.     

Wuhan University Journal of Natural Sciences TOTAL CONTENTS

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Scale-based spatial data model for GIS

Being the primary media of geographical information and the elementary objects manipulated, almost all of maps adopt the layer-based model to represent geographic information in the existent GIS. However, it is difficult to extend the map represented in layer-based model. Furthermore, in Web-Based GIS, It is slow to transmit the spatial data for map viewing. In this paper, for solving the questions above, we have proposed a new method for representing the spatial data. That is scale-based model. In this model we represent maps in three levels: scale-view, block, and spatial object, and organize the maps in a set of map layers, named Scale-View, which associates some given scales.Lastly, a prototype Web-Based GIS using the proposed spatial data representation is described briefly.     

英文诗歌中的喻类修辞

为了有助于提高英文爱好者的个人情操、文化素养和学习兴趣,以及专业人员对英语学习和研究进行多途径的探索,本文通过一些精选诗歌的引证和分析,着重论述了喻类修辞法在英文诗歌中的运用其及效果。     

Man Is Unable to Change the Miserable Life——Analysis of the Arrangement of Four Characters in The Glass Menagerie

Tennessee Williams is considered as one of the most important American playwrights since World War II.The Glass Menagerie is his first successful drama,which describes a tragic situation of family and means to say that Man is unable to change the miserable life,no matter whatever means he try,This essay focuses on the analysis of the arrangement of the four main characters:Laura.Amanda,Jim and Tom to reveal the theme.Laura is fragile.Amanda is brave.Jim is vital.Tom is sensible.And all of them develop and try the different means to struggle against life,but fail tragically.With the evidence,the paper comes to conclusion naturally that Man is unable to change the miserable life,and he dooms to fail.     

Characterization of root-nodulating bacteria on Retama raetam in arid Tunisian soils

The aim of this study is to investigate the diversity of Retama raetam root-nodule bacteria isolated from arid regions of Tunisia. Twelve isolates, chosen as representative for different 16S rRNA gene patterns, were characterized by 16S rRNA gene sequencing and phenotypic analysis. Isolates were assigned to Sinorhizobium, Rhizobium and Agrobacterium. Symbiotic properties of Sinorhizobium and Rhizobium isolates showed a large diversity in their capacity to infect their host plant and fix atmospheric nitrogen. Strain RK 22 identified as Rhizobium was the most effective isolate.     

An Affordable Accurate Evaluation of the Binding Conformations Predicted by Molecular Docking Studies in Bio-System

正Recently,docking has been widely used to predict the binding-modes of protein-inhibitors,when the crystal complexes structure was absent.Most docking algorithms are able to generate a large number of probable conformations,it,however,is difficult to effectively evaluate these docking poses and identify the most reasonable bindingmode.In the present study,on the basis of the crystallographic data of human 3-hydroxy-3-methylglutaryl coenzyme     

WIMAX与WI-FI技术分析及联合组网

介绍了WiMAX与Wi-Fi两种无线宽带接入技术,并对两者之间的关系及相互之间的影响做了对比及分析,并对WiMAX的关键技术进行了详细说明,最后对两者的联合组网方式做了简单的探讨。